Preheat your oven to 350°F (175°C).
Cook the elbow macaroni according to package instructions until al dente. Drain and set aside.
In a large mixing bowl, combine the shredded chicken, BBQ sauce, cheddar cheese, mozzarella cheese, cream cheese, milk, garlic powder, onion powder, black pepper, and salt. Stir until well combined.
Add the cooked macaroni to the chicken and cheese mixture, stirring until the pasta is evenly coated.
Transfer the mixture to a greased 9x13 inch baking dish.
If using breadcrumbs, mix them with olive oil in a small bowl, then sprinkle evenly over the mac and cheese.
Bake in the preheated oven for 25-30 minutes, or until the cheese is bubbly and the top is golden brown.
Remove from the oven and let it cool for 5 minutes before serving.