Preheat your oven to 350°F (175°C).
In a large bowl, combine cooked pasta and shredded chicken.
Add the Alfredo sauce, garlic powder, and Italian seasoning to the bowl.
Mix until the pasta and chicken are well coated.
Transfer the mixture to a greased baking dish.
Sprinkle mozzarella, cheddar, and Parmesan cheese evenly on top.
Season with salt and pepper to taste.
Bake in the preheated oven for 25-30 minutes until the cheese is bubbly and golden brown.
Remove from the oven and let it cool for 5 minutes.
Garnish with fresh parsley before serving.