diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index a355f34..0669a21 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -31,7 +31,7 @@ jobs:
       matrix:
         # Note: we temporarily pin to macos-12 to avoid compatibility issues
         # between AT22+ and macos-13+ runners
-        os: [ubuntu-latest]
+        os: ["ubuntu-latest", "macos-latest"]
         python-version: ["3.10"]
 
     steps:
@@ -60,9 +60,9 @@ jobs:
 
     - name: Environment Information
       run: |
-        conda info
-        conda list
+        micromamba info
+        micromamba list
 
     - name: Run example notebooks
       run: |
-        python -m pytest -v setup/ showcase/ cookbook/ openmm_rbfe/ networks/ --nbval-lax -n auto --dist loadscope
+        python -m pytest -v setup/ showcase/ cookbook/ openmm_rbfe/ networks/ --nbval-lax --nbval-cell-timeout=3000 -n auto --dist loadscope