01 - Preheat oven to 350°F. Lightly grease a 9x13 inch baking dish.
02 - Boil pasta in salted water until just al dente. Drain well and set aside.
03 - In a large mixing bowl, whisk together buffalo wing sauce, cream cheese, sour cream, whole milk, garlic powder, onion powder, smoked paprika, salt, and black pepper until completely smooth.
04 - Add cooked chicken and drained pasta to the bowl. Mix thoroughly to coat every piece evenly in the sauce.
05 - Fold in half of the shredded mozzarella and all of the cheddar cheese.
06 - Spread the mixture evenly into the prepared baking dish.
07 - Top with the remaining mozzarella cheese and crumbled blue cheese, if using.
08 - Place the baking dish uncovered on the center rack and bake for 25 to 30 minutes, or until hot, bubbling, and golden on the surface.
09 - Remove from oven and allow to cool for 5 minutes. Scatter sliced green onions and parsley over the top before serving.