1Cook the elbow macaroni according to the package instructions. Drain and set aside.
In a large saucepan, melt the butter over medium heat.
Add the flour to the melted butter and whisk continuously for about 1-2 minutes to form a roux.
Gradually add the milk to the roux, whisking constantly to avoid lumps. Continue to cook and whisk until the mixture thickens, about 5-7 minutes.
Reduce the heat to low and add the shredded cheddar cheese to the sauce. Stir until the cheese is completely melted and the sauce is smooth.
Add the salt and black pepper to the cheese sauce and mix well.
Add the cooked macaroni and diced chicken breast to the cheese sauce. Stir until everything is well combined and heated through.
Serve the Cheesy Mac with Chicken hot and enjoy!