1Heat oven to 350°F. In 10-inch skillet, cook beef over medium heat 8 to 10 minutes, stirring occasionally, until brown; drain. Stir in beans and 1 cup salsa. Heat to boiling, stirring occasionally.
2In ungreased 2-quart casserole, place broken tortilla chips. Top with beef mixture. Sprinkle with onions, tomato and cheese.
3Bake uncovered 20 to 30 minutes or until hot and bubbly. Arrange tortilla chips around edge of casserole. Serve with lettuce and additional salsa.