Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine the bite-sized pieces of chicken with garlic powder, black pepper, salt, and dried oregano. Mix well.
Add the canned diced tomatoes (with their juices) and chicken broth to the bowl with the chicken. Stir until well mixed.
In your casserole dish, spread half of the herb seasoned bread crumbs evenly across the bottom.
Pour the chicken and tomato mixture over the bed of bread crumbs, spreading it out evenly.
Sprinkle the remaining bread crumbs over the chicken mixture, then add the part-skim mozzarella cheese on top.
Place the casserole in the preheated oven and bake for 30-35 minutes, or until the chicken is cooked through and the cheese is bubbly and golden brown.
Once baked, remove the casserole from the oven and allow it to cool for a few minutes before serving.