In a large bowl, combine cheeses; set aside 1 cup for topping. Add the beans, tomatoes, cream cheese, sour cream and taco seasoning to the remaining cheese. Transfer to a 2-qt. baking dish coated with cooking spray; sprinkle with reserved cheese. Bake, uncovered, at 350° for 20-25 minutes or until bubbly around the edges. Serve warm with tortilla chips and vegetables.