01 - Preheat the oven to 350°F.
02 - In a medium mixing bowl, thoroughly combine the softened cream cheese, sour cream, hot sauce, ranch dressing, garlic powder, and black pepper until the mixture is smooth.
03 - Gently fold in the shredded cooked chicken breast, shredded cheddar cheese, and shredded mozzarella cheese until all components are evenly distributed.
04 - Transfer the prepared dip mixture into an 8-inch baking dish, spreading it out evenly.
05 - Bake for 20 to 25 minutes, or until the dip is heated through and visibly bubbly around the edges.
06 - Remove the baking dish from the oven. If desired, sprinkle the sliced green onions over the hot dip.
07 - Serve the spicy buffalo chicken dip immediately with tortilla chips, celery sticks, or sliced baguette.