Members of the NixOS community maintain a package of Polychromatic.

With a command

nix-shell -p polychromatic

Or… by updating configuration.nix

environment.systemPackages = with pkgs; [

Then rebuild your system:

sudo nixos-rebuild switch

Next up, OpenRazer

Polychromatic is just a frontend. If you haven't already, you'll need to install this driver and daemon: