Preheat the oven: Heat the oven to 350°F (175°C).
Lightly grease a small baking dish (8x8-inch or similar).
Soften the cream cheese: In a medium bowl, beat the softened cream cheese with a spoon or hand mixer until smooth. This helps everything blend evenly.
Build the base: Stir in the buffalo sauce and ranch dressing until fully combined. Taste and adjust the heat by adding more sauce if you like it spicier.
Add the chicken and cheese: Fold in the shredded chicken, 3/4 cup of the cheddar, and all the mozzarella.
Add a few grinds of black pepper.
Transfer and top: Spread the mixture evenly in the prepared baking dish. Sprinkle the remaining 1/4 cup cheddar over the top. If using, scatter a little crumbled blue cheese on top as well.
Bake: Bake for 20–25 minutes, until hot and bubbling around the edges and the top is melted.
Garnish and serve: Let it sit for 5 minutes.
Sprinkle with chopped green onions. Serve warm with chips, veggies, or bread.