Preheat the oven to 350°F. Cook the elbow macaroni according to package instructions until al dente. Drain and set aside.
In a large saucepan, melt the butter over medium heat. Stir in the flour and cook for about 1 minute, stirring constantly to create a roux.
Gradually whisk in the milk, continuing to stir until the mixture thickens, about 3-5 minutes. Remove from heat.
Stir in the cheddar and mozzarella cheeses, garlic powder, onion powder, black pepper, salt, and cayenne pepper (if using) until the cheese is melted and the sauce is smooth.
In a separate bowl, combine the honey, soy sauce, olive oil, and crushed red pepper flakes (if using). Add the chicken breasts and coat them well with the mixture.
Heat a skillet over medium-high heat and cook the chicken for 5-7 minutes on each side, or until fully cooked and golden brown. Remove from heat and let it rest for a few minutes before slicing.
In a large mixing bowl, combine the cooked macaroni and cheese sauce. Stir until the pasta is well coated.
Transfer the mac and cheese to a greased baking dish. Top with sliced honey pepper chicken.
Bake in the preheated oven for 20 minutes, or until bubbly and golden on top. Garnish with chopped parsley before serving.