In a large bowl, combine the cooked pasta, shredded chicken, buffalo sauce, ricotta cheese, 1/2 cup of the mozzarella cheese, sour cream, garlic powder, onion powder, salt, and pepper. Mix well until the ingredients are fully incorporated.
Transfer the mixture to a greased 9x13 inch baking dish, spreading it evenly with a spatula.
Sprinkle the remaining mozzarella cheese and grated Parmesan cheese over the top of the pasta mixture.
Cover the baking dish with aluminum foil and bake in the preheated oven for 20 minutes.
After 20 minutes, remove the foil and bake for an additional 10-15 minutes, or until the cheese is bubbly and slightly golden.
Once baked, remove from the oven and let it cool for a few minutes. Garnish with sliced green onions before serving.
Notes
Serve hot with extra buffalo sauce and celery sticks for a complete meal.