In a large pot or Dutch oven, melt the butter over medium heat. Add the breadcrumbs and stir occasionally until the breadcrumbs are toasted. Transfer to a bowl and set aside. 

Heat 1 tablespoon of the oil in the pot over medium. Add the diced chicken and Italian seasoning. Cook the chicken for 4-5 minutes, tossing occasionally. Transfer to a plate and set aside (it's okay if the chicken isn’t cooked through all the way).

Heat the remaining 1 tablespoon oil over medium in the large pot. Add the onion and garlic and sauté for 2-3 minutes, until the onion is translucent.

Add the chicken back to the pot, along with the dry pasta, marinara sauce, and chicken broth. Bring to a boil, then reduce to a simmer. Cover and cook for 12-15 minutes, until the pasta is cooked al dente. 

Uncover, stir in the cheeses, and heat until the cheese is melted. Top with the breadcrumb topping, garnish with herbs, and serve!