diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 25dee0fb89..40d57fd23f 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -53,6 +53,9 @@ jobs:
         uses: actions/checkout@v2
       - name: Install Nix
         uses: cachix/install-nix-action@v12
+        with:
+          # used only for providing a more recent `bash` on macOS
+          nix_path: nixpkgs=channel:nixos-unstable
         if: matrix.os != 'windows-latest'
       - name: Install MSYS2
         uses: msys2/setup-msys2@v2