POWER OF ATTORNEY

        The undersigned hereby constitutes and appoints each of Paul Hastings,
Chief Executive Officer of Nkarta, Inc., a Delaware corporation (the "Company"),
and Matthew Plunkett, Chief Financial Officer of the Company, the undersigned's
true and lawful attorney-in-fact to:

        1       execute for and on behalf of the undersigned, in the
                undersigned's capacity as an officer and/or director of the
                Company, Forms 3, 4, and 5 in accordance with Section 16(a) of
                the Securities Exchange Act of 1934, as amended and the rules
                thereunder (the "Exchange Act"), and/or authenticating documents
                pursuant to the rules governing the SEC's EDGAR Filer Management
                and application thereto;

        2       do and perform any and all acts for and on behalf of the
                undersigned which may be necessary or desirable to complete and
                execute any such Form 3, 4, or 5, complete and execute any
                amendment or amendments thereto, and timely file such form with
                the United States Securities and Exchange Commission and any
                stock exchange or similar authority; and

        3       take any other action of any type whatsoever in connection with
                the foregoing which, in the opinion of such attorney-in-fact,
                may be of benefit to, in the best interest of, or legally
                required by, the undersigned, it being understood that the
                documents executed by such attorney-in-fact on behalf of the
                undersigned pursuant to this Power of Attorney shall be in such
                form and shall contain such terms and conditions as such
                attorney-in-fact may approve in such attorney-in-fact's
                discretion.

        The undersigned hereby grants to such attorney-in-fact full power and
authority to do and perform any and every act and thing whatsoever requisite,
necessary, or proper to be done in the exercise of any of the rights and powers
herein granted, as fully to all intents and purposes as the undersigned might or
could do if personally present, with full power of substitution or revocation,
hereby ratifying and confirming all that such attorney-in-fact, or such
attorney-in-fact's substitute or substitutes, shall lawfully do or cause to be
done by virtue of this power of attorney and the rights and powers herein
granted.

        The undersigned acknowledges that:

        1       neither the Company nor the foregoing attorney-in-fact assumes
                (i) any liability for the undersigned's responsibility to comply
                with the requirement of the Exchange Act, (ii) any liability of
                the undersigned for any failure to comply with such requirements
                or (iii) any obligation or liability of the undersigned for
                profit disgorgement under Section 16(b) of the Exchange Act; and

        2       this Power of Attorney does not relieve the undersigned from
                responsibility for compliance with the undersigned's obligations
                under the Exchange Act, including without limitation the
                reporting requirements under Section 16 of the Exchange Act.

        This Power of Attorney shall remain in full force and effect until the
undersigned is no longer required to file Forms 3, 4, and 5 with respect to the
undersigned's holdings of and transactions in securities issued by the Company
unless earlier revoked by the undersigned in a signed writing delivered to each
attorney-in-fact.

                     [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK.]

        IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to
be executed as of this 7th day of July, 2020.

                                        /s/ Fouad O. Azzam
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                                        FOUAD O. AZZAM