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. Mix until the consistency is smooth and well-blended.
03 - Gently fold in the shredded cooked chicken, shredded cheddar cheese, and shredded mozzarella cheese until all components are evenly distributed throughout the mixture.
04 - Transfer and spread the prepared dip mixture evenly into an 8-inch baking dish.
05 - Bake for 20 to 25 minutes, or until the dip is heated through, bubbly around the edges, and the cheese is melted and lightly golden.
06 - Remove the baking dish from the oven. If desired, sprinkle the sliced green onions over the hot dip just before serving.
07 - Serve the spicy buffalo chicken dip immediately with an accompaniment of tortilla chips, crisp celery sticks, or toasted baguette slices.