Preheat oven to 350 degrees F. Coat a medium baking dish with cooking spray and set aside. In a medium bowl, combine the shredded chicken, cream cheese, bbq sauce, red onion, Worcestershire sauce, 2 cups of cheddar cheese, garlic salt and pepper. Mix well and pour into the prepared baking dish.
Cover with a lid or foil and bake in the preheated oven for 15 minutes, or until heated through. Remove the cover and top with an even layer of the remaining ½ cup of cheese. Place back in the oven for 5 more minutes, or until the cheese has melted. Serve warm with chips and crackers. Drizzle with additional bbq sauce, if desired.