diff --git a/overlay.nix b/overlay.nix
index 8b0ae80..5c3c589 100644
--- a/overlay.nix
+++ b/overlay.nix
@@ -21,11 +21,6 @@ let
     "nurl"
     "prefetch-yarn-deps" # force these onto upstream so we are not regularly rebuilding electron
   ];
-  override_2_18 = prev.lib.genAttrs overridelist_2_18 (
-    name: prev.${name}.override {
-      nix = final.nixVersions.nix_2_18_upstream;
-    }
-  );
 
   inherit (prev) lib;
 
@@ -65,7 +60,12 @@ let
   # errors. This is a simple safeguard to put in at least something that might be seen.
   maybeWarnWrongMajor = x: if !(lib.hasPrefix supportedLixMajor lixPackageToUse.version) then builtins.trace wrongMajorWarning x else x;
 
-  overlay = override_2_18 // {
+  overlay = 
+    lib.genAttrs overridelist_2_18 (
+      name: if (lib.functionArgs prev.${name}.override ? "nix") then prev.${name}.override {
+        nix = final.nixVersions.nix_2_18_upstream;
+      } else prev.${name}
+    ) // {
     lix-overlay-present = 1;
     # used for things that one wouldn't necessarily want to update, but we
     # nevertheless shove it in the overlay and fixed-point it in case one *does*