Preheat oven to 350 degrees F. Crumble ground beef into a 10-inch skillet. Add onion. Cook and stir until beef is light brown and onion is tender. Drain. Add kidney beans (undrained), tomato sauce, chili powder and garlic salt. Heat to boiling. Pour half of the meat mixture into ungreased 1 1/2-quart casserole and top with broken tortilla chips.
Pour remaining beef mixture over top and sprinkle with Cheddar cheese. Cover and bake for 25 to 30 minutes or until bubbly. Garnish with chopped green pepper and pimento, if desired.