Preheat the oven to 375°F (190°C).
In a large mixing bowl, combine the uncooked rice, chicken broth, Italian dressing, chopped onion, minced garlic, dried Italian seasoning, salt, and black pepper. Stir well to combine.
Add the cut chicken pieces, diced red bell pepper, and thawed peas to the rice mixture. Stir until all ingredients are evenly distributed.
Transfer the mixture to a 9×13-inch casserole dish and spread it out evenly.
Cover the casserole dish tightly with aluminum foil.
Bake in the preheated oven for 40 minutes.
Remove the casserole from the oven and carefully remove the foil.
Sprinkle the shredded mozzarella cheese and grated Parmesan cheese evenly over the top.
Return the casserole to the oven, uncovered, and bake for an additional 5 minutes or until the cheese is melted and bubbly.
Remove from the oven and let the casserole rest for 5 minutes before serving.