nixos/system/steam.nix

{ pkgs, ... }: {
  environment.systemPackages = with pkgs; [ mesa ];
  hardware = {
    opengl.driSupport32Bit = true;
    steam-hardware.enable = true;
  };
  programs = {
    xwayland.enable = true;
    gamescope = {
      enable = true;
      capSysNice = true;
    };
    steam = {
      enable = true;
      remotePlay.openFirewall = true;
    };
  };
}