Can I pass in an overlay?

flake.nix

@@ -37,6 +37,6 @@
           inherit (self.packages."${prev.system}") wallfly;
         };
 
-        nixosModule = import ./module.nix;
+        nixosModule = import ./module.nix self.overlay;
       };
 }

module.nix

@@ -1,3 +1,5 @@
+wallfly-overlay:
+
 { config, lib, pkgs, ... }:
 
 with lib;
@@ -49,6 +51,8 @@ in {
   };
 
   config = mkIf cfg.enable {
+    nixpkgs.overlays = [ wallfly-overlay ];
+
     systemd.user.services.wallfly = {
       wantedBy = [ "multi-user.target" ];
       after = [ "network-online.target" ];