Heat a drizzle of olive oil in a large Dutch oven or deep skillet over medium-high heat.
Season chicken pieces with salt, pepper, Italian seasoning, and garlic powder. Add to hot pan and cook about 5 minutes, stirring occasionally, until mostly cooked through. Remove to a plate.
In the same pot, add minced onion. Cook 2-3 minutes until softened. Add minced garlic and cook 1 minute until fragrant.
Pour in marinara sauce. Fill empty sauce jar with water and add to pot. Stir and bring to a boil, then reduce to a strong simmer.
Add cooked chicken and dried pasta to the pot. Stir to combine. Cover with lid.
Cook 10-15 minutes, stirring every few minutes, until pasta is cooked to desired tenderness. If mixture looks dry before pasta is done, add a splash more water.
When pasta is tender, stir in parmesan cheese and ¼ cup of the mozzarella cheese.
Sprinkle remaining ¾ cup mozzarella evenly over top. Cover and cook 2-3 minutes until cheese is melted and gooey.
Remove from heat. Garnish with fresh herbs if desired and serve immediately.