Preheat and prep. Heat your oven to 375°F (190°C). Lightly grease a small baking dish (about 8x8 inches or a 1.5–2 quart dish).
Soften and mix the base. In a mixing bowl, beat the softened cream cheese until smooth.
Stir in the hot sauce, ranch or blue cheese dressing, and melted butter if using. You want a silky, well-blended base.
Add the chicken. Fold in the shredded chicken until every piece is coated. If the mixture looks too thick, add a tablespoon of dressing to loosen it.
Stir in the cheese. Mix in half of the cheddar and half of the mozzarella.
If you’re using blue cheese crumbles, add half now and save the rest for topping.
Assemble the dip. Spread the mixture evenly into your baking dish. Top with the remaining cheddar and mozzarella, plus the rest of the blue cheese crumbles if using.
Bake until bubbly. Bake for 18–22 minutes, or until the edges are bubbling and the top is lightly golden. If you want extra browning, broil for 1–2 minutes at the end.
Finish and serve. Let it rest for 5 minutes so it sets slightly.
Sprinkle with green onions or chives. Serve warm with chips and crunchy veggies.