For the kind of person who wants to run NixOS on Apple Silicon or do Linux gaming on Apple Silicon in the first place, that's probably interesting and not too hard
but if you're allergic to that, you might be able to figure something else out with Box64, which is already packaged in Nixpkgs
x86_64 gaming on NixOS is of course well supported and has been for a long time. There's a 'native' package that I've always used and the Steam Flatpak is also available and works as well as it does anywhere