1Heat oven to 350ºF. In 2-quart saucepan, cook beef and onion stirring frequently, until beef is brown and onion is tender; drain.
2In small bowl, mix 1 tablespoon Bisquick mix, the chili powder and water; add to beef mixture. Stir in tomatoes, corn and salt. Heat to boiling, stirring frequently. Pour into ungreased 8-inch square (2-quart) glass baking dish or 2-quart casserole.
3Stir remaining ingredients until blended; pour over beef mixture.
4Bake uncovered 35 to 40 minutes or until golden brown.