1. Cook the macaroni: Bring a large pot of salted water to a boil. Add the elbow macaroni and cook according to package directions until al dente. Drain well and set aside. Do not rinse the pasta, as the starch helps the sauce adhere better.

2. Start the roux: In the same large pot (or a separate large saucepan), melt the butter over medium heat. Once melted, sprinkle in the flour and whisk continuously for 1-2 minutes until a smooth paste forms. This is your roux, which will thicken the sauce.

3. Whisk in the milk: Gradually pour in the milk, whisking constantly to prevent lumps. Continue to whisk until the mixture is smooth and starts to thicken, about 3-5 minutes. It should gently coat the back of a spoon.

4. Add seasonings and cheese: Stir in the garlic powder, onion powder, black pepper, and salt. Reduce the heat to low. Add the shredded cheddar and Monterey Jack cheeses, stirring until they are completely melted and the sauce is smooth and creamy.

5. Incorporate buffalo sauce and chicken: Remove the pot from the heat. Stir in the buffalo wing sauce until well combined. Then, gently fold in the cooked shredded or diced chicken.

6. Combine with pasta: Add the drained cooked macaroni to the cheese sauce mixture. Stir gently until all the macaroni is evenly coated with the creamy buffalo chicken sauce.

7. Serve and garnish: Transfer the mac and cheese to serving bowls. If desired, sprinkle with blue cheese crumbles and chopped fresh parsley before serving. Enjoy immediately while warm and gooey.