diff --git a/nix/default.nix b/nix/default.nix
index 2e9dd5a78..d993c1a19 100644
--- a/nix/default.nix
+++ b/nix/default.nix
@@ -1,2 +1,3 @@
-{ pkgs ? import <nixpkgs> { overlays = [ (import ./overlays.nix) ]; } }:
-pkgs.python2.pkgs.callPackage ./tahoe-lafs.nix { }
+{ pkgs ? import <nixpkgs> { } }:
+let pkgs' = import pkgs.path { overlays = [ (import ./overlays.nix) ]; };
+in pkgs'.python2.pkgs.callPackage ./tahoe-lafs.nix { }