• Chop or shred the cooked chicken breast and hold it aside.
• Cook the pasta in salted water according to package directions. Drain the pasta well and set it aside.
• Preheat the oven to 350° F. Spray a 9-inch x 13-inch baking dish with nonstick spray. 
•  In a large-sized bowl, whisk together the Greek yogurt, ranch dressing mix and hot sauce. Add the chopped or shredded chicken to this mixture and toss the coat the chicken pieces thoroughly with the sauce.

Make the roux and cheese sauce:

• In a large saucepan, melt the butter over medium heat. When the butter just begins to simmer add in the flour, salt and pepper. Stir this constantly for 1 minute until it is thickened.
• Slowly add in the milk and stir it together with the butter mixture. Bring the mixture to a simmer over medium heat, stirring often so that it doesn’t burn on the bottom. The mixture should thicken as it comes to a simmer - once it begins thickening remove it from the heat. Stir in the shredded cheese until it is melted and the cheese sauce is smooth.
• Pour the cheese sauce into the bowl with the buffalo chicken mixture and stir everything together.
• Add in the cooked pasta and stir to coat the noodles with the sauce. When everything is combined, pour it into the prepared baking pan and spread it into an even layer. Cover the pan with foil.
• Bake the macaroni & cheese for 30 minutes. Remove the foil and bake it for an additional 15 minutes.
• Let the mac and cheese cool for a few minutes and then serve. Enjoy!