Bring a large pot of salted water to a boil and cook the elbow macaroni until al dente. Drain and set aside.
In a medium saucepan, melt the butter over medium heat. Whisk in the flour and cook for about 1 minute to make a light paste.
Slowly whisk in the milk, breaking up any lumps. Let the mixture simmer gently until it thickens, about 2–3 minutes.
Stir in the softened cream cheese until smooth, then add the cheddar cheese. Stir until melted and glossy.
Add the buffalo sauce, salt, and black pepper. Taste and adjust the heat if needed.
Fold in the shredded chicken so it heats through, then mix in the cooked macaroni until well coated.
If you like a crust, transfer the mac and cheese to a greased baking dish, sprinkle with a light dusting of extra cheddar, and bake at 375°F (190°C) for 12–15 minutes until bubbly and golden on top.
Garnish with blue cheese crumbles and chopped green onions if using. Serve hot and enjoy the balance of creamy, spicy, and comforting flavors.