Heat oven to 350°F. Lightly grease a small baking dish.
Soften cream cheese until spreadable. Microwave briefly or let sit at room temperature.
Whisk cream cheese with hot sauce, ranch, and sour cream until smooth.
Stir in chicken, mozzarella, and about 1 cup cheddar. Season with garlic powder, onion powder, pepper, and salt.
Spread mixture in the dish. Sprinkle remaining cheddar over the top.
Bake until hot and bubbly, 18–22 minutes. Broil 1–2 minutes to brown the cheese, if desired.
Rest 5 minutes. Garnish with green onions and blue cheese. Serve warm with celery, carrots, or chips.