01 - Preheat oven to 375°F. Lightly grease a 9x13-inch casserole dish with cooking spray or butter.
02 - In a large skillet over medium heat, warm a drizzle of oil. Sauté the diced onion, celery, and sliced jalapeños until softened, about 4 to 5 minutes. Add the minced garlic and cook for 1 additional minute, stirring constantly.
03 - In a large mixing bowl, combine the softened cream cheese, sour cream, Buffalo wing sauce, salt, black pepper, and smoked paprika. Stir until smooth and well blended.
04 - Fold the shredded chicken, sautéed vegetables, half of the cheddar cheese, and half of the mozzarella into the creamy sauce mixture. Stir until all ingredients are evenly incorporated.
05 - Transfer the mixture into the prepared casserole dish, spreading it into an even layer. Sprinkle the remaining cheddar and mozzarella cheeses evenly over the top.
06 - Bake uncovered for 25 to 30 minutes, or until the cheese is melted, bubbly, and lightly golden on top.
07 - Remove from the oven and scatter blue cheese crumbles and sliced green onions over the surface, if desired.
08 - Allow the casserole to rest for 5 minutes before slicing and serving. This helps the filling set for cleaner portions.