Heat 1–2 tablespoons olive oil in a Dutch oven over medium heat.
Add the diced chicken, Italian seasoning, garlic powder, onion powder, and garlic salt; stir to coat and cook until the chicken is mostly cooked through, about 4–6 minutes.
Add the minced onion and garlic paste to the pot; cook, stirring occasionally, until the onion is soft and translucent, about 5–7 minutes.
Pour in the pasta sauce and chicken stock, then add the rigatoni; stir to combine and bring to a low simmer.
Cover and simmer gently for 12–14 minutes, stirring occasionally, until the pasta is tender and most of the liquid is absorbed.
Stir in 1/2 cup shredded mozzarella until melted and evenly distributed.
Top the pasta with the remaining mozzarella and the Parmesan; cover briefly until the cheeses melt, about 2–3 minutes.
Season with salt and pepper to taste, garnish with chopped parsley, and serve.