<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2025 Workiva-->
<!--r:26c2f74f-5c83-4759-b92a-de43240a10e1,g:94fcd6ae-92c5-4b1b-a782-8230c61c2d17-->
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:next="http://www.next-decade.com/20250331" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:dtr-types1="http://www.xbrl.org/dtr/type/2020-01-21" xmlns:dtr-types="http://www.xbrl.org/dtr/type/2022-03-31" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" attributeFormDefault="unqualified" elementFormDefault="qualified" targetNamespace="http://www.next-decade.com/20250331">
  <xs:import namespace="http://fasb.org/srt/2024" schemaLocation="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd"/>
  <xs:import namespace="http://fasb.org/us-gaap/2024" schemaLocation="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd"/>
  <xs:import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd"/>
  <xs:import namespace="http://www.xbrl.org/2003/linkbase" schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd"/>
  <xs:import namespace="http://www.xbrl.org/dtr/type/2020-01-21" schemaLocation="https://www.xbrl.org/dtr/type/2020-01-21/types.xsd"/>
  <xs:import namespace="http://www.xbrl.org/dtr/type/2022-03-31" schemaLocation="https://www.xbrl.org/dtr/type/2022-03-31/types.xsd"/>
  <xs:import namespace="http://xbrl.org/2005/xbrldt" schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/dei/2024" schemaLocation="https://xbrl.sec.gov/dei/2024/dei-2024.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/ecd/2024" schemaLocation="https://xbrl.sec.gov/ecd/2024/ecd-2024.xsd"/>
  <xs:annotation>
    <xs:appinfo>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="next-20250331_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="next-20250331_def.xml" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="next-20250331_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="next-20250331_cal.xml" xlink:role="http://www.xbrl.org/2003/role/calculationLinkbaseRef" xlink:type="simple"/>
      <link:roleType id="CoverPage" roleURI="http://www.next-decade.com/role/CoverPage">
        <link:definition>0000001 - Document - Cover Page</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ConsolidatedBalanceSheets" roleURI="http://www.next-decade.com/role/ConsolidatedBalanceSheets">
        <link:definition>9952151 - Statement - Consolidated Balance Sheets</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ConsolidatedBalanceSheetsParentheticals" roleURI="http://www.next-decade.com/role/ConsolidatedBalanceSheetsParentheticals">
        <link:definition>9952152 - Statement - Consolidated Balance Sheets (Parentheticals)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ConsolidatedStatementsofOperations" roleURI="http://www.next-decade.com/role/ConsolidatedStatementsofOperations">
        <link:definition>9952153 - Statement - Consolidated Statements of Operations</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ConsolidatedStatementofStockholdersEquityandConvertiblePreferredStock" roleURI="http://www.next-decade.com/role/ConsolidatedStatementofStockholdersEquityandConvertiblePreferredStock">
        <link:definition>9952154 - Statement - Consolidated Statement of Stockholders' Equity and Convertible Preferred Stock</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ConsolidatedStatementsofCashFlows" roleURI="http://www.next-decade.com/role/ConsolidatedStatementsofCashFlows">
        <link:definition>9952155 - Statement - Consolidated Statements of Cash Flows</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BackgroundandBasisofPresentation" roleURI="http://www.next-decade.com/role/BackgroundandBasisofPresentation">
        <link:definition>9952156 - Disclosure - Background and Basis of Presentation</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="PropertyPlantandEquipment" roleURI="http://www.next-decade.com/role/PropertyPlantandEquipment">
        <link:definition>9952157 - Disclosure - Property, Plant and Equipment</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Derivatives" roleURI="http://www.next-decade.com/role/Derivatives">
        <link:definition>9952158 - Disclosure - Derivatives</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Leases" roleURI="http://www.next-decade.com/role/Leases">
        <link:definition>9952159 - Disclosure - Leases</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="AccruedLiabilitiesandOtherCurrentLiabilities" roleURI="http://www.next-decade.com/role/AccruedLiabilitiesandOtherCurrentLiabilities">
        <link:definition>9952160 - Disclosure - Accrued Liabilities and Other Current Liabilities</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Debt" roleURI="http://www.next-decade.com/role/Debt">
        <link:definition>9952161 - Disclosure - Debt</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="VariableInterestEntity" roleURI="http://www.next-decade.com/role/VariableInterestEntity">
        <link:definition>9952162 - Disclosure - Variable Interest Entity</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockholdersEquity" roleURI="http://www.next-decade.com/role/StockholdersEquity">
        <link:definition>9952163 - Disclosure - Stockholders' Equity</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SharebasedCompensation" roleURI="http://www.next-decade.com/role/SharebasedCompensation">
        <link:definition>9952164 - Disclosure - Share-based Compensation</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CommitmentsandContingencies" roleURI="http://www.next-decade.com/role/CommitmentsandContingencies">
        <link:definition>9952165 - Disclosure - Commitments and Contingencies</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SupplementalCashFlows" roleURI="http://www.next-decade.com/role/SupplementalCashFlows">
        <link:definition>9952166 - Disclosure - Supplemental Cash Flows</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="PropertyPlantandEquipmentTables" roleURI="http://www.next-decade.com/role/PropertyPlantandEquipmentTables">
        <link:definition>9955511 - Disclosure - Property, Plant and Equipment (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DerivativesTables" roleURI="http://www.next-decade.com/role/DerivativesTables">
        <link:definition>9955512 - Disclosure - Derivatives (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LeasesTables" roleURI="http://www.next-decade.com/role/LeasesTables">
        <link:definition>9955513 - Disclosure - Leases (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="AccruedLiabilitiesandOtherCurrentLiabilitiesTables" roleURI="http://www.next-decade.com/role/AccruedLiabilitiesandOtherCurrentLiabilitiesTables">
        <link:definition>9955514 - Disclosure - Accrued Liabilities and Other Current Liabilities (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DebtTables" roleURI="http://www.next-decade.com/role/DebtTables">
        <link:definition>9955515 - Disclosure - Debt (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="VariableInterestEntityTables" roleURI="http://www.next-decade.com/role/VariableInterestEntityTables">
        <link:definition>9955516 - Disclosure - Variable Interest Entity (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SupplementalCashFlowsTables" roleURI="http://www.next-decade.com/role/SupplementalCashFlowsTables">
        <link:definition>9955517 - Disclosure - Supplemental Cash Flows (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BackgroundandBasisofPresentationDetails" roleURI="http://www.next-decade.com/role/BackgroundandBasisofPresentationDetails">
        <link:definition>9955518 - Disclosure - Background and Basis of Presentation (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="PropertyPlantandEquipmentScheduleofPropertyPlantandEquipmentDetails" roleURI="http://www.next-decade.com/role/PropertyPlantandEquipmentScheduleofPropertyPlantandEquipmentDetails">
        <link:definition>9955519 - Disclosure - Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DerivativesInterestRateSwapsOutstandingDetails" roleURI="http://www.next-decade.com/role/DerivativesInterestRateSwapsOutstandingDetails">
        <link:definition>9955520 - Disclosure - Derivatives - Interest Rate Swaps Outstanding (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DerivativesNarrativeDetails" roleURI="http://www.next-decade.com/role/DerivativesNarrativeDetails">
        <link:definition>9955521 - Disclosure - Derivatives - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LeasesNarrativeDetails" roleURI="http://www.next-decade.com/role/LeasesNarrativeDetails">
        <link:definition>9955522 - Disclosure - Leases - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LeasesMaturityofOperatingLeasesDetails" roleURI="http://www.next-decade.com/role/LeasesMaturityofOperatingLeasesDetails">
        <link:definition>9955523 - Disclosure - Leases - Maturity of Operating Leases (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LeasesMaturityofOperatingLeasesDetails_1" roleURI="http://www.next-decade.com/role/LeasesMaturityofOperatingLeasesDetails_1">
        <link:definition>9955523 - Disclosure - Leases - Maturity of Operating Leases (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="AccruedLiabilitiesandOtherCurrentLiabilitiesScheduleofAccruedLiabilitiesandOtherCurrentLiabilitiesDetails" roleURI="http://www.next-decade.com/role/AccruedLiabilitiesandOtherCurrentLiabilitiesScheduleofAccruedLiabilitiesandOtherCurrentLiabilitiesDetails">
        <link:definition>9955524 - Disclosure - Accrued Liabilities and Other Current Liabilities - Schedule of Accrued Liabilities and Other Current Liabilities (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DebtScheduleofDebtDetails" roleURI="http://www.next-decade.com/role/DebtScheduleofDebtDetails">
        <link:definition>9955525 - Disclosure - Debt - Schedule of Debt (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DebtNarrativeDetails" roleURI="http://www.next-decade.com/role/DebtNarrativeDetails">
        <link:definition>9955526 - Disclosure - Debt - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DebtTermLoanUnpaidInterestDetails" roleURI="http://www.next-decade.com/role/DebtTermLoanUnpaidInterestDetails">
        <link:definition>9955527 - Disclosure - Debt - Term Loan, Unpaid Interest (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DebtScheduleofCreditFacilitiesOutstandingDetails" roleURI="http://www.next-decade.com/role/DebtScheduleofCreditFacilitiesOutstandingDetails">
        <link:definition>9955528 - Disclosure - Debt - Schedule of Credit Facilities Outstanding (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DebtScheduleofInterestExpenseDetails" roleURI="http://www.next-decade.com/role/DebtScheduleofInterestExpenseDetails">
        <link:definition>9955529 - Disclosure - Debt - Schedule of Interest Expense (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DebtCarryingAmountandFairValueofDebtDetails" roleURI="http://www.next-decade.com/role/DebtCarryingAmountandFairValueofDebtDetails">
        <link:definition>9955530 - Disclosure - Debt - Carrying Amount and Fair Value of Debt (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="VariableInterestEntityDetails" roleURI="http://www.next-decade.com/role/VariableInterestEntityDetails">
        <link:definition>9955531 - Disclosure - Variable Interest Entity (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockholdersEquityDetails" roleURI="http://www.next-decade.com/role/StockholdersEquityDetails">
        <link:definition>9955532 - Disclosure - Stockholders' Equity (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SharebasedCompensationNarrativeDetails" roleURI="http://www.next-decade.com/role/SharebasedCompensationNarrativeDetails">
        <link:definition>9955533 - Disclosure - Share-based Compensation - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SupplementalCashFlowsDetails" roleURI="http://www.next-decade.com/role/SupplementalCashFlowsDetails">
        <link:definition>9955534 - Disclosure - Supplemental Cash Flows (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
    </xs:appinfo>
  </xs:annotation>
  <xs:element id="next_NonCurrentCommonStockWarrantLiabilities" abstract="false" name="NonCurrentCommonStockWarrantLiabilities" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="next_StockIssuedDuringPeriodValueWarrantsExercised" abstract="false" name="StockIssuedDuringPeriodValueWarrantsExercised" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="next_NetCashProvidedBySettlementOfDerivativeInstruments" abstract="false" name="NetCashProvidedBySettlementOfDerivativeInstruments" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="next_NoncashInterestExpenseAndAmortizationOfDebtIssuanceCosts" abstract="false" name="NoncashInterestExpenseAndAmortizationOfDebtIssuanceCosts" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="next_InvestingActivitiesOtherNoncurrentAssets" abstract="false" name="InvestingActivitiesOtherNoncurrentAssets" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="next_CostsAssociatedWithRepaymentsOfDebt" abstract="false" name="CostsAssociatedWithRepaymentsOfDebt" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="next_ScheduleOfAccruedExpensesAndOtherCurrentLiabilitiesTableTextBlock" abstract="false" name="ScheduleOfAccruedExpensesAndOtherCurrentLiabilitiesTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:textBlockItemType"/>
  <xs:element id="next_RioGrandeLiquefiedNaturalGasFacilityMember" abstract="true" name="RioGrandeLiquefiedNaturalGasFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="next_LiquefactionTrainFourMember" abstract="true" name="LiquefactionTrainFourMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="next_LiquefactionTrainFiveMember" abstract="true" name="LiquefactionTrainFiveMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="next_NumberOfLiquefactionTrainsAuthorized" abstract="false" name="NumberOfLiquefactionTrainsAuthorized" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="next_LiquefiedNaturalGasExportAuthorizedMass" abstract="false" name="LiquefiedNaturalGasExportAuthorizedMass" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:massItemType"/>
  <xs:element id="next_NumberOfLiquefactionTrains" abstract="false" name="NumberOfLiquefactionTrains" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="next_NumberOfLiquefactionTrainsUnderDevelopment" abstract="false" name="NumberOfLiquefactionTrainsUnderDevelopment" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="next_RioGrandeMember" abstract="true" name="RioGrandeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="next_LesseeOperatingLeaseNumberOfConsecutiveRenewalTerm" abstract="false" name="LesseeOperatingLeaseNumberOfConsecutiveRenewalTerm" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="next_LesseeOperatingLeaseLiabilityToBePaidAfterYearFour" abstract="false" name="LesseeOperatingLeaseLiabilityToBePaidAfterYearFour" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="next_BusinessAcquisitionDeferredTransactionCostsCurrent" abstract="false" name="BusinessAcquisitionDeferredTransactionCostsCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="next_SeniorSecuredNotesMember" abstract="true" name="SeniorSecuredNotesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="next_SeniorSecuredLoansMember" abstract="true" name="SeniorSecuredLoansMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="next_SeniorSecuredNotesAndLoansMember" abstract="true" name="SeniorSecuredNotesAndLoansMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="next_CdSeniorWorkingCapitalFacilityMember" abstract="true" name="CdSeniorWorkingCapitalFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="next_CdCreditFacilityMember" abstract="true" name="CdCreditFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="next_TcfCreditFacilityMember" abstract="true" name="TcfCreditFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="next_CorporateCreditFacilityMember" abstract="true" name="CorporateCreditFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="next_A6.67SeniorSecuredNotesMember" abstract="true" name="A6.67SeniorSecuredNotesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="next_A6.85SeniorSecuredNotesMember" abstract="true" name="A6.85SeniorSecuredNotesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="next_A6.58SeniorSecuredNotesMember" abstract="true" name="A6.58SeniorSecuredNotesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="next_A6.72SeniorSecuredLoansMember" abstract="true" name="A6.72SeniorSecuredLoansMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="next_A7.11SeniorSecuredLoansMember" abstract="true" name="A7.11SeniorSecuredLoansMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="next_A12.00CorporateCreditAgreementMember" abstract="true" name="A12.00CorporateCreditAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="next_CorporateCreditAgreementMember" abstract="true" name="CorporateCreditAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="next_CdCreditFacilityAndTcfCreditFacilityMember" abstract="true" name="CdCreditFacilityAndTcfCreditFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="next_PaidInKindInterestElectedNumberOfAdditionalInterestPayments" abstract="false" name="PaidInKindInterestElectedNumberOfAdditionalInterestPayments" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="next_PercentageOfPaymentsEligibleToBePaidInKind" abstract="false" name="PercentageOfPaymentsEligibleToBePaidInKind" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="next_DebtInstrumentCovenantMinimumPercentageOfProjectedPrincipalAmountOutstandingBeHedged" abstract="false" name="DebtInstrumentCovenantMinimumPercentageOfProjectedPrincipalAmountOutstandingBeHedged" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="next_DebtInstrumentCovenantHistoricalDebtServiceCoverageRatioMinimum" abstract="false" name="DebtInstrumentCovenantHistoricalDebtServiceCoverageRatioMinimum" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="next_DebtInstrumentCovenantRepurchasePricePercentage" abstract="false" name="DebtInstrumentCovenantRepurchasePricePercentage" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="next_WarrantTrancheAxis" abstract="true" name="WarrantTrancheAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="next_WarrantTrancheDomain" abstract="true" name="WarrantTrancheDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="next_WarrantTrancheAMember" abstract="true" name="WarrantTrancheAMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="next_WarrantTrancheBMember" abstract="true" name="WarrantTrancheBMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="next_WarrantNumberOfTranches" abstract="false" name="WarrantNumberOfTranches" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="next_NumberOfDaysUsedToDetermineVolumeWeightedAverageTradingPrice" abstract="false" name="NumberOfDaysUsedToDetermineVolumeWeightedAverageTradingPrice" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="next_VolumeWeightedAverageTradingPriceThresholdMinimum" abstract="false" name="VolumeWeightedAverageTradingPriceThresholdMinimum" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType"/>
  <xs:element id="next_ServiceBasedRestrictedStockMemberMember" abstract="true" name="ServiceBasedRestrictedStockMemberMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="next_AccountsPayableAcquisitionOfPropertyPlantAndEquipment" abstract="false" name="AccountsPayableAcquisitionOfPropertyPlantAndEquipment" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="next_AccruedLiabilitiesAcquisitionOfPropertyPlantAndEquipment" abstract="false" name="AccruedLiabilitiesAcquisitionOfPropertyPlantAndEquipment" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="next_NoncashOrPartNoncashSettlementOfWarrantLiabilities" abstract="false" name="NoncashOrPartNoncashSettlementOfWarrantLiabilities" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
</xs:schema>
