Step 1: Prepare the Oven and Dish
Preheat your oven to 425°F.
Spray a 9×13 baking dish lightly with cooking spray or oil to prevent sticking.

Step 2: Season the Chicken
In a large bowl, toss the diced chicken with minced garlic, Italian seasoning, and oregano. Let the chicken sit for about 5 minutes to absorb the flavors.

Step 3: Assemble the Casserole
In the prepared baking dish, combine the uncooked rigatoni pasta, marinara sauce, water, seasoned chicken, salt, and black pepper. Stir everything together right in the dish to evenly distribute the ingredients.

Step 4: Bake the First Round
Cover the baking dish tightly with aluminum foil. Bake in the preheated oven for 30 minutes to allow the pasta to cook and the flavors to meld.

Step 5: Add the Cheesy Topping
After 30 minutes, carefully remove the foil and stir the casserole. The pasta will still be slightly firm, and there will be extra liquid, but that’s expected.

Step 6: Finish Baking
Sprinkle the top with shredded mozzarella, Panko breadcrumbs, and Parmesan cheese. Return the casserole to the oven uncovered and bake for another 10-15 minutes until the cheese is golden and bubbly and the pasta is fully tender.

Step 7: Garnish and Serve
Remove the casserole from the oven and sprinkle generously with chopped fresh basil. Let it rest for a few minutes before serving to allow the flavors to settle.