Cook the Pasta: Bring a large pot of water to a boil. Add a generous pinch of salt, then cook the macaroni pasta according to the package instructions. Once cooked, drain and set aside, reserving a small amount of pasta water.
Cook the Chicken: While the pasta is cooking, cut the chicken breast into small bite-sized pieces. Heat the olive oil in a large pan over medium heat, then add the chicken. Sauté until the chicken is golden and cooked through, about 5-7 minutes. Add the buffalo sauce to the chicken, stir to coat, and let it simmer for 2-3 minutes to meld the flavors.
Make the Sauce: Pour in the heavy cream, then add salt, pepper, and nutmeg. Stir well. Once the cream is combined, add the shredded cheddar and grated parmesan, stirring until the cheese is fully melted and the sauce is smooth.
Combine Pasta and Sauce: Add a little of the reserved pasta water to the sauce, if needed, to adjust the consistency. Stir in the cooked pasta until it's well coated with the sauce.
Serve: Transfer to a serving dish, garnish with fresh parsley, and enjoy your delicious Buffalo Chicken Mac and Cheese!
