Preheat your oven to 350°F (175°C).

Cook the elbow macaroni according to package instructions until al dente. Drain and set aside.

In a large mixing bowl, combine the shredded chicken and buffalo sauce, mixing until the chicken is well coated.

In a separate saucepan over medium heat, combine the cream cheese, milk, garlic powder, onion powder, salt, and black pepper. Stir until the cream cheese is melted and the mixture is smooth.

Add the cooked macaroni to the cream cheese mixture, stirring to combine. Then, fold in the buffalo chicken mixture and half of the cheddar and mozzarella cheeses.

Pour the macaroni and cheese mixture into a greased 9x13 inch baking dish. Top with the remaining cheddar and mozzarella cheeses.

Bake in the preheated oven for 20-25 minutes, or until the cheese is bubbly and golden brown.

Remove from the oven and let it cool for 5 minutes. Garnish with sliced green onions and blue cheese crumbles, if desired.