Creating Baked Chicken Parmesan Casserole is simple if you follow these straightforward steps:

1. Preheat Oven: Preheat your oven to 350°F (175°C).
2. Prepare Chicken: In a large bowl, combine shredded chicken with marinara sauce, Italian seasoning, garlic powder, salt, and black pepper. Mix well to coat the chicken evenly in the sauce.
3. Layer Ingredients: In a greased 9×13 inch baking dish, spread half of the chicken mixture in an even layer.
4. Add Cheese: Sprinkle half of the mozzarella and half of the Parmesan cheese on top of the chicken layer.
5. Repeat Layers: Spread the remaining chicken mixture over the cheese layer and top with the remaining mozzarella and Parmesan cheese.
6. Breadcrumb Topping: In a small bowl, mix the seasoned breadcrumbs with olive oil, then sprinkle them evenly over the cheese layer.
7. Bake: Cover the casserole with aluminum foil and bake in the preheated oven for 25 minutes. Then, remove the foil and bake for an additional 15-20 minutes until the cheese is bubbly and golden.
8. Cool Down: Once out of the oven, let the casserole cool for 5-10 minutes before serving. This helps firm up the layers for easier slicing.
9. Garnish: Add fresh basil leaves on top for an extra touch of flavor and color before serving.

By following these steps, you will have an incredible Baked Chicken Parmesan Casserole that will excite your taste buds and warm your heart!