01 - Preheat oven to 375°F. Lightly grease a 9x13-inch casserole dish with nonstick cooking spray or butter.
02 - In a large mixing bowl, combine the softened cream cheese, ranch dressing, and buffalo wing sauce. Stir vigorously until the mixture is completely smooth and free of any cream cheese lumps.
03 - Fold the shredded chicken and cooked pasta into the sauce base. Add 1 1/2 cups of the cheddar cheese and 1/2 cup of the mozzarella cheese. Mix thoroughly until every piece of chicken and pasta is evenly coated.
04 - Transfer the entire mixture into the prepared casserole dish, spreading it out into an even layer. Scatter the remaining 1/2 cup cheddar and 1/2 cup mozzarella across the top. If desired, sprinkle with blue cheese crumbles and panko breadcrumbs for extra texture.
05 - Bake uncovered on the center oven rack for 30 to 35 minutes, until the cheese is fully melted, the edges are bubbling, and the top is lightly golden.
06 - Remove from the oven and let rest for 5 minutes. Scatter the sliced green onions over the top and serve hot directly from the dish.