split some things and add my packages

modules/nix.nix

@@ -0,0 +1,36 @@
+{ lib, pkgs, inputs, config, ... }:
+{
+  environment.variables = {
+    NIXPKGS_ALLOW_UNFREE = "1";
+  };
+
+  nixpkgs.flake.setNixPath = true;
+  nixpkgs.flake.setFlakeRegistry = true;
+
+  nix = {
+    package = pkgs.nixVersions.latest;
+
+    settings = {
+      experimental-features = [ "nix-command" "flakes" ];
+
+      auto-optimise-store = true;
+
+      keep-outputs = true;
+      keep-derivations = true;
+
+      substituters = [
+        "https://nix-community.cachix.org"
+      ];
+      trusted-public-keys = [
+        "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
+      ];
+    };
+  };
+
+  nix.optimise.automatic = true;
+  nix.gc = {
+    automatic = true;
+    dates = "weekly";
+    options = "--delete-older-than 30d";
+  };
+}