Preheat your oven to 350°F (175°C).
In a saucepan, bring the chicken broth to a boil. Add the uncooked rice, reduce heat to low, cover, and let simmer for 18-20 minutes, or until the rice is cooked and the liquid is absorbed.
If using fresh broccoli, heat olive oil in a skillet over medium heat. Sauté the broccoli for about 3-4 minutes until bright green and slightly tender. If using frozen broccoli, skip this step.
In a large mixing bowl, combine the shredded chicken, cooked rice, sautéed broccoli, cream of mushroom soup, milk, garlic powder, onion powder, salt, and pepper. Mix until well combined.
Transfer the mixture into a greased 9x13-inch casserole dish. Sprinkle the shredded cheddar cheese evenly over the top.
If desired, mix breadcrumbs with a tablespoon of melted butter and sprinkle over the cheese for a crunchy topping.
Bake in the preheated oven for 25-30 minutes, or until the cheese is bubbly and golden brown.
Remove from the oven and let it cool for a few minutes before serving.