Preheat the oven to 350°F (175°C).
Season the chicken breasts with garlic powder, Italian seasoning, salt, and pepper. Cook in a large pot of boiling water for about 15 minutes, or until fully cooked. Remove from water, let cool slightly, then cube the chicken.
In a mixing bowl, combine the cubed chicken with the marinara sauce.
In a greased 9x13 inch baking dish, layer half of the cooked penne pasta at the bottom. Spread half of the chicken and marinara mixture over the pasta. Sprinkle half of the mozzarella and Parmesan cheese on top.
Repeat the layers with the remaining ingredients, finishing with the cheese on top.
Cover the baking dish with aluminum foil and bake for 25 minutes.
Remove the foil and bake for an additional 15 minutes, or until the cheese is bubbly and golden.
Let the casserole sit for 5-10 minutes before serving.
Optional: Add vegetables such as spinach or bell peppers for extra nutrition before layering.