Heat a large dutch oven over medium low heat and add in 1 tsp oil and diced chicken. Cook chicken through, then remove from the pot. Add in remaining oil and diced onions and cook until onions begin to get tender and translucent. Stir and cook until garlic is fragrant.
Add in 3 cups of water or broth and can of crushed tomatoes. Stir in pasta and seasonings and bring to a boil.
Once boiling, reduce heat to medium and cook for 15-20 minutes, stirring occasionally, or until all liquid is absorbed. The mixture will continue to thicken once heat is off.
Once thickened, stir in the cooked chicken and 1/2 cup mozzarella cheese. Turn off heat.
Pour the rest of the mozzarella cheese on top, in addition to the parmesan. It will melt as it cools.
Alternatively, you can place the pasta mixture in a broiler safe dish, top with cheese and breadcrumbs, and broil for a few minutes watching carefully until cheese is brown and bubbly.
Enjoy with addition parmesan cheese, if desired! I usually top with extra pecorino romano to make it a perfect blue!