01 - Preheat oven to 375°F. Lightly grease a 9x13-inch casserole dish.
02 - In a skillet over medium heat, sauté onion, celery, and jalapeños in a small amount of oil until softened, about 4–5 minutes. Stir in garlic and cook 1 minute more.
03 - In a large bowl, combine softened cream cheese, sour cream, Buffalo wing sauce, salt, black pepper, and smoked paprika. Mix until smooth.
04 - Stir in the cooked chicken, sautéed vegetables, half of the cheddar cheese, and half of the mozzarella. Mix well to combine evenly.
05 - Spread the mixture evenly into the prepared casserole dish. Top with remaining cheddar and mozzarella cheeses.
06 - Bake, uncovered, for 25–30 minutes, until cheese is bubbly and golden on top.
07 - Remove from oven. Scatter blue cheese crumbles and sliced green onions over the top if desired. Let rest 5 minutes before serving.