diff --git a/.github/workflows/nix.yml b/.github/workflows/nix.yml
index b3f72c2..c2df15f 100644
--- a/.github/workflows/nix.yml
+++ b/.github/workflows/nix.yml
@@ -19,10 +19,15 @@ jobs:
         include:
           - runner: ubuntu-latest
             system: x86_64-linux
+            flags: ""
           - runner: ubuntu-24.04-arm
             system: aarch64-linux
+            flags: ""
           - runner: macos-latest
             system: aarch64-darwin
+            # The bsdkrun dependency has no libkrun in nixpkgs on macOS — its
+            # flake links Homebrew's libkrun impurely (LIBKRUN_PREFIX).
+            flags: "--impure"
     runs-on: ${{ matrix.runner }}
 
     steps:
@@ -32,8 +37,12 @@ jobs:
       - name: Install Nix
         uses: DeterminateSystems/nix-installer-action@main
 
+      - name: Install libkrun (macOS)
+        if: runner.os == 'macOS'
+        run: brew install tsirysndr/tap/libkrun
+
       - name: Build kbuildx
-        run: nix build ".#packages.${{ matrix.system }}.kbuildx" --print-build-logs
+        run: nix build ".#packages.${{ matrix.system }}.kbuildx" --print-build-logs ${{ matrix.flags }}
 
       - name: Verify packaged CLI
         run: ./result/bin/kbuildx --version