01 - Preheat oven to 375°F.
02 - Combine softened cream cheese, sour cream, ranch dressing, Buffalo sauce, garlic powder, and black pepper in a large mixing bowl. Mix until smooth and fully incorporated.
03 - Fold in shredded chicken, cheddar cheese, and mozzarella cheese until evenly distributed throughout the mixture.
04 - Transfer mixture to a 9-inch oven-safe baking dish and spread into an even layer.
05 - Bake for 20-25 minutes until hot and bubbly with golden top.
06 - Remove from oven and let cool for 5 minutes. Garnish with sliced green onions if desired.
07 - Serve warm with tortilla chips for dipping.