Heat oven to 400. Spray cooking spray on bottom of a 2-quart casserole dish; set aside. In a skillet, cook chicken, onion, peppers, and garlic clove until tender. Add seasoning mix and taco sauce; set aside. In a medium bowl, combine sour cream and cottage cheese; set aside. Place half the broken chips in the bottom of casserole dish. Add meat mixture to cover the chips, then cover the meat with sour cream mixture. Sprinkle with cheese and remaining crushed chips. Bake, uncovered, for 30 minutes or until cheese has melted. Top with 3/4 cup salsa if desired.