surely this works

flake.nix

@@ -25,6 +25,11 @@
       url = "github:Mic92/sops-nix";
       inputs.nixpkgs.follows = "nixpkgs";
     };
+
+    nixpak = {
+      url = "github:nixpak/nixpak";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
   };
 
   outputs = { 
@@ -36,6 +41,7 @@
     disko,
     sops-nix,
     secrets,
+    nixpak,
     ...
   } @ inputs: let
     lib = nixpkgs.lib.extend (final: prev: 

modules/nixos/core/nix.nix

@@ -1,8 +1,8 @@
-{ lib, inputs, cfgPath, ... }:
+{ pkgs, lib, inputs, cfgPath, ... }:
 
 let
   importOverlays = builtins.map
-    (overlay: import overlay { inherit lib inputs; })
+    (overlay: import overlay { inherit lib inputs pkgs; })
     (builtins.filter 
       (file: builtins.match ".*\.nix" (builtins.toString file) != null)
       (lib.filesystem.listFilesRecursive "${cfgPath}/overlays"));

overlays/nixpak/default.nix

@@ -0,0 +1,6 @@
+{ inputs, pkgs, lib, ... }: final: prev: {
+  mkNixPak = inputs.nixpak.lib.nixpak {
+    inherit (pkgs) lib;
+    inherit pkgs;
+  };
+}