diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index dfd3c4017..e11e21c25 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -143,6 +143,8 @@ jobs:
       fail-fast: true
     steps:
     - uses: actions/checkout@v6
+    # Remove unneeded cruft in runner so we have room for Nix:
+    - uses: wimpysworld/nothing-but-nix@main
     - uses: cachix/install-nix-action@v31
       with:
         nix_path: nixpkgs=channel:nixos-unstable