NixOS-Config/modules/system/settings/nix/default.nix

{ ... }:
{
  imports = [
    ./autoupgrade
  ];

  nix.settings = {
    experimental-features = [
      "nix-command"
      "flakes"
    ];
    auto-optimise-store = true;
  };

  nixpkgs.config.allowUnfree = true;
}