Preheat your oven to 350 degrees F. This is an important first step as it ensures that your casserole bakes evenly.
Spray a 9 x 9 baking dish with nonstick spray. This will prevent your casserole from sticking and make cleanup easier later on.
In a large mixing bowl, combine the pre-cooked pasta, chicken, and marinara sauce. Stir until everything is well blended; you want that sauce to coat everything!
Pour the mixture into the prepared baking dish. Spread it out evenly to make sure it bakes uniformly.
Top with the shredded mozzarella cheese. Don’t be shy here; the more cheese, the better!
Place the dish in the oven and bake uncovered for 15 to 20 minutes. You’ll know it’s ready when the cheese is bubbly and golden.
Once it's done, remove it from the oven and let it sit for a few minutes. This helps it set a bit, making it easier to serve.
Serve hot and enjoy! I love to pair this with a side salad for a complete meal.
