Guix even comes with a Nix service[0] which is easy to enable if you would like to also use Nix packages.
[0] https://guix.gnu.org/manual/en/html_node/Miscellaneous-Servi...
[0] https://guix.gnu.org/manual/en/html_node/Miscellaneous-Servi...
It's a cute little testament to the fundamental strengths of the functional package management paradigm, as well as helping users on either side of the fence fill some gaps in a pinch and providing more/easier opportunities to compare notes and inspire improvements.