diff --git a/sdk/lib/_internal/js_runtime/lib/js_helper.dart b/sdk/lib/_internal/js_runtime/lib/js_helper.dart
index dc4b6e3..2af7e18 100644
--- a/sdk/lib/_internal/js_runtime/lib/js_helper.dart
+++ b/sdk/lib/_internal/js_runtime/lib/js_helper.dart
@@ -3882,7 +3882,7 @@
     var script = JS('', 'document.createElement("script")');
     JS('', '#.type = "text/javascript"', script);
     JS('', '#.src = #', script, uri);
-    if (_cspNonce != '') {
+    if (_cspNonce != null && _cspNonce != '') {
       JS('', '#.nonce = #', script, _cspNonce);
     }
     JS('', '#.addEventListener("load", #, false)', script, jsSuccess);
diff --git a/tests/compiler/dart2js_extra/deferred_with_csp_nonce_test.dart b/tests/compiler/dart2js_extra/deferred_with_csp_nonce_test.dart
index c9fd2db..90d6acb 100644
--- a/tests/compiler/dart2js_extra/deferred_with_csp_nonce_test.dart
+++ b/tests/compiler/dart2js_extra/deferred_with_csp_nonce_test.dart
@@ -18,7 +18,7 @@
       .where((s) => s.src.contains("generated_compilations"))
       .toList();
   Expect.equals(1, scripts.length);
-  Expect.equals('', scripts.first.nonce);
+  Expect.equals('', scripts.first.nonce ?? '');
   scripts.first.nonce = "an-example-nonce-string";
 
   lib.loadLibrary().then((_) {