Preheat your oven to 375°F. Grease a baking dish (9x13 inches) lightly with cooking spray or butter.
Bring a large pot of salted water to a boil. Cook the rotini pasta according to the package instructions until it's al dente. Drain the pasta and set it aside.
Combine ingredients in a large mixing bowl. Add the cooked rotini pasta, diced or shredded chicken, Alfredo sauce, garlic parmesan sauce, half of the shredded mozzarella cheese, and half of the grated Parmesan cheese. Season with salt and pepper to taste.
Mix everything together until well combined. If needed add about ½ cup pasta water. You want the casserole dish to be good and saucy!
Pour the pasta mixture into the greased baking dish and spread it out evenly.
Sprinkle the remaining shredded mozzarella cheese and grated Parmesan cheese evenly over the top of the pasta mixture.
Cover with aluminum foil. Place the baking dish in the preheated oven and bake for about 20-25 minutes, or until the cheese is melted and bubbly, and the pasta bake is heated through.
If desired, place the casserole under the broiler for 2-3 minutes until the top of the casserole is golden brown. Watch it carefully though, you don't want it to burn!
Once done, remove the pasta bake from the oven and let it cool for 5 minutes covered with aluminum foil. Garnish with chopped fresh parsley if desired. Serve warm and enjoy!