<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2020-06-24</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001137887</issuerCik>
        <issuerName>Nuveen Municipal Credit Income Fund</issuerName>
        <issuerTradingSymbol>NZF</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000835271</rptOwnerCik>
            <rptOwnerName>JPMorgan Chase Bank, N.A.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1111 POLARIS PARKWAY</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>COLUMBUS</rptOwnerCity>
            <rptOwnerState>OH</rptOwnerState>
            <rptOwnerZipCode>43240</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Series C MuniFund Preferred Shares</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3360</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F1"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Trust</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The 3,360 Series C MuniFund Preferred Shares (&quot;MFP Shares&quot;) reported as acquired in Table I represent MFP Shares of the Issuer beneficially owned by JPMorgan Chase Bank, National Association (&quot;JPMCB&quot;).  On June 25, 2020 JPMCB acquired the MFP Shares from the Issuer and on July 6, 2020, JPMCB deposited the MFP Shares into a trust designated as the J.P. Morgan PUTTERs/DRIVERs, Series 5039 Trust (the &quot;Trust&quot;).  JPMCB, as a beneficiary of the Trust and through its contractual rights, retains an indirect beneficial ownership in the MFP Shares.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>JPMORGAN CHASE BANK, NATIONAL ASSOCIATION, by: /s/ Sean Saroya</signatureName>
        <signatureDate>2020-07-06</signatureDate>
    </ownerSignature>
</ownershipDocument>
