--- a/taskcluster/ci/build/macosx.yml
+++ b/taskcluster/ci/build/macosx.yml
@@ -126,17 +126,17 @@ macosx64-nightly/opt:
         nightly: true
     index:
         product: firefox
         job-name: macosx64-opt
         type: nightly
     treeherder:
         platform: osx-cross/opt
         symbol: tc(N)
-        tier: 2
+        tier: 1
     worker-type: aws-provisioner-v1/gecko-{level}-b-macosx64
     worker:
         max-run-time: 36000
         env:
             TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/macosx64/cross-releng.manifest"
     run:
         using: mozharness
         actions: [get-secrets build update]