Heat oven to 325°F Grease rectangular pan, 13- x 9- x 2-inches.
Cook ground beef and onion in 10-inch skillet, stirring frequently, until beef is brown; drain. Stir in dry seasoning mix, tomato sauce, and corn. Spoon into pan; sprinkle with cheese. Stir Bisquick mix, milk and eggs until smooth. Pour over beef mixture.
Bake about 35 minutes or until knife inserted in center comes out clean. Cool 10 minutes before cutting. Serve with remaining ingredients.