nixos-config/system/systemd.nix

{ ... }:
{
  systemd.services.lact = {
    description = "AMDGPU Control Daemon";
    after = ["multi-user.target"];
    wantedBy = ["multi-user.target"];
    serviceConfig = {
      ExecStart = "${pkgs.lact}/bin/lact daemon";
    };
    enable = true;
};
}