In a large dutch oven, over medium heat, melt butter and add your breadcrumbs. Toast until golden (1-2 minutes), then remove onto a bowl and set aside.
Add oil to the same dutch oven over medium high heat, add the chicken and immediately season it with salt, pepper, and Italian seasoning. Add the onion, and saute for 2 minutes until the onion softens. Then add garlic, and cook for 30 seconds. The chicken won’t be fully cooked but that’s okay as it will be cooked further with the pasta.
Deglaze the bottom of the pot with ½ cup of chicken stock, then add the pasta, marinara, and the remaining chicken stock.
Stir well to coat the pasta in the liquid. Bring to a boil, then reduce heat, cover, and simmer for 11-13 minutes, stirring intermittently, until pasta is al dente. Remove from heat.
Add ½ cup of shredded mozzarella, parmesan cheese, and stir to combine.
Sprinkle the crunchy breadcrumbs on top of the pasta, and the remaining mozzarella cheese. Cover with a lid, and allow it to sit for 5 minutes. The sauce will thicken, and the cheese will melt. Garnish with fresh basil, and serve.