In a shallow 1-1/2qt microwave safe dish, combine the sour cream, beans, chillies and dip mix. Stir in 1 cup cheese. Cover and microwave on high for 3 minutes. Stir, rotate dish a quarter turn. Cover and microwave 2 minutes longer or until heated through. Sprinkle with remaining cheese. Top with olives, tomatoes, onions and lettuce if desired. Serve with tortilla chips.