1. Prepare Oven and Dish:

• Preheat the oven to 425°F (220°C).
• Spray a 9×13 inch baking dish generously with cooking spray or lightly grease with oil.

2. Season the Chicken:

• Place the diced chicken breast pieces into a bowl.
• Add the minced garlic, Italian seasoning, and oregano. Toss well to ensure the chicken is evenly coated. Let it sit for about 5 minutes while you prepare the dish.

3. Combine Ingredients in Baking Dish:

• Add the uncooked rigatoni pasta directly into the prepared baking dish.
• Pour the marinara sauce over the pasta.
• Pour the 3 cups of water over the pasta and sauce.
• Add the seasoned raw chicken pieces to the dish.
• Sprinkle the salt and black pepper evenly over everything.
• Stir all the ingredients together directly within the baking dish until well combined. Make sure the pasta and chicken are mostly submerged in the liquid.

4. Bake Covered:

• Cover the baking dish tightly with aluminum foil. This is crucial to trap steam and cook the pasta and chicken properly.
• Carefully place the covered dish into the preheated oven.
• Bake covered for 30 minutes.

5. Stir and Check Liquid:

• Carefully remove the dish from the oven and remove the foil (watch out for steam!).
• Give the mixture a good stir. At this point, there will likely still be a good amount of liquid in the dish, and the pasta will not be fully cooked yet. This is normal and expected.

6. Add Topping and Bake Uncovered:

• Sprinkle the shredded mozzarella evenly over the pasta mixture.
• Top the mozzarella evenly with the Panko breadcrumbs.
• Sprinkle the grated Parmesan cheese over the breadcrumbs.
• Return the dish uncovered to the oven.
• Bake for another 10-15 minutes, or until the cheese is melted, golden brown, and bubbly, and the pasta is tender when tested.

7. Garnish and Serve:

• Let the casserole rest for 5-10 minutes after removing it from the oven.
• Sprinkle with fresh chopped basil just before serving.
• Serve hot.