Heat oven to 375. Cook beef in 10" skillet over medium heat 8-10 minutes, stirring occasionally, until brown; drain. Mix beef, beans, tomato sauce, salsa, and chili powder in ungreased 2 qt. casserole. Cover and bake 40-45 minutes, stirring once or twice, until hot and bubbly. Sprinkle with cheese. Bake uncovered about 5 minutes or until cheese is melted.