In large nonstick skillet, cook meat and onion until meat is done; drain excess fat. Add enchilada sauce, tomato sauce, black beans and corn, stirring well. Cut biscuits into fourths and stir into meat mixture.
Transfer to prepared pan. Bake 25 minutes. Remove from oven, sprinkle with cheese and green onions. Return to oven and bake 5-7 minutes more or until cheese is melted.