Preheat oven 375°F. Whisk softened cream cheese, chicken broth, soy sauce, minced garlic, sesame oil, pepper in bowl using wooden spoon till smooth lump-free.
Spread ½ cup sauce bottom 9x13 baking dish using measuring cup. Nestle frozen dumplings snug single layer. Pour remaining sauce even over top.
Sprinkle mozzarella full cover using measuring cup. Scatter half sliced scallions even.
Bake middle rack 25 minutes till sauce bubbles cheese golden brown spots. Broil 2 minutes watch close for crisp.
Rest 5 minutes. Sprinkle remaining scallions. Scoop hot serve.