Creating BBQ Chicken Mac and Cheese is straightforward when you follow these steps:

1. Boil the Pasta: Start by boiling a large pot of salted water. Cook the elbow macaroni according to package instructions until al dente. Drain and set aside.
2. Preheat the Oven: Preheat your oven to 350°F (175°C).
3. Make the Cheese Sauce: In a large saucepan over medium heat, melt the butter. Once melted, whisk in the flour and cook for about 1 minute until bubbly.
4. Add Milk and Spices: Gradually whisk in the milk, garlic powder, onion powder, salt, and pepper. Cook until the mixture is slightly thickened, about 3-5 minutes.
5. Stir in Cheese: Remove the saucepan from heat and add in the shredded cheddar and mozzarella cheese, stirring until melted and smooth.
6. Combine Chicken and BBQ Sauce: In a separate bowl, mix the shredded chicken with the BBQ sauce until fully coated.
7. Combine Everything: In a large mixing bowl, combine the cooked macaroni, cheese sauce, and BBQ chicken mixture. Stir until evenly mixed.
8. Transfer to Baking Dish: Pour the mac and cheese mixture into a greased 9×13 inch baking dish, spreading it evenly.
9. Bake: Place in the preheated oven and bake for 25-30 minutes, or until the top is golden brown and bubbly.
10. Garnish: Remove from the oven, let it cool for a few minutes, and garnish with fresh parsley if desired.

These steps will guide you in creating this amazing BBQ Chicken Mac and Cheese with ease.