Creating the Cheesy Pesto Chicken Casserole is straightforward. Just follow these easy steps:

1. Preheat Oven: Begin by preheating your oven to 375°F (190°C).
2. Prepare the Dish: Grease a 9×13-inch baking dish with cooking spray or olive oil.
3. Mix Chicken and Pesto: In a large bowl, combine the shredded chicken and pesto sauce, mixing well until the chicken is fully coated.
4. Add Pasta: Fold in the cooked pasta, ricotta cheese, garlic powder, and Italian seasoning. Stir until evenly combined.
5. Season to Taste: Add salt and pepper to taste, adjusting according to your preference.
6. Layer in the Dish: Pour the chicken and pasta mixture into the prepared baking dish, spreading it evenly.
7. Top with Cheese: Sprinkle the shredded mozzarella and grated Parmesan cheese evenly over the top.
8. Bake: Place the casserole in the preheated oven and bake for 30-35 minutes or until the cheese is bubbly and golden brown.
9. Cool Slightly: Once done, remove the casserole from the oven and let it cool for about 5 minutes.
10. Garnish and Serve: If desired, garnish with fresh basil leaves before serving.

This step-by-step guide makes it easy to create a delicious Cheesy Pesto Chicken Casserole that will impress everyone at your table.