Prep. Heat oven to 375F. Lightly grease a small baking dish (about 8x8).
Mix. In a bowl, stir together cream cheese, ranch (or blue cheese) dressing, hot sauce, and sour cream (if using) until smooth.
Add chicken and cheese. Fold in shredded chicken and half of the cheddar and mozzarella.
Top. Spread into the baking dish and sprinkle remaining cheese over the top.
Bake. Bake 18 to 22 minutes until hot and bubbling around the edges.
Finish. Optional: broil 1 to 2 minutes for a golden top. Top with green onions and serve warm.