Preheat oven to 375°F (190°C). Grease a 9x13 inch baking dish.

Boil rigatoni in salted water until 2 minutes shy of al dente. Reserve 1/2 cup pasta water, then drain pasta.

Toss chicken chunks with salt, pepper, and garlic powder. Heat olive oil in a large skillet over medium-high heat. Sear chicken until golden brown and cooked through (about 6-7 minutes). Remove chicken and set aside.

In the same skillet over medium heat, sauté minced garlic for 30 seconds. Pour in chicken broth, scraping up browned bits. Add heavy cream and simmer gently for 3-4 minutes to thicken.

Remove skillet from heat. Whisk in basil pesto and 1/2 cup of parmesan cheese. (Add a splash of reserved pasta water if the sauce is too thick).

Add the drained rigatoni and cooked chicken back into the skillet, tossing well to coat everything in the sauce.

Pour the mixture into the prepared baking dish. Top evenly with shredded mozzarella and the remaining 1/2 cup of parmesan cheese.

Bake uncovered for 15-20 minutes until bubbly and golden brown on top.

Let rest for 5 minutes. Garnish with fresh parsley and red pepper flakes before serving.