Preheat your oven to 350°F and lightly grease a 9x13 baking dish.
Spread the cooked rice evenly at the bottom of the dish. If using the Knorr mix, stir it in now.
Layer the cubed chicken on top of the rice, sprinkling with garlic powder, salt, and pepper.
In a medium bowl, combine the cream of chicken soup, sour cream, and half of the shredded cheese. Mix well.
Pour the mixture over the chicken and spread it evenly.
Add the broccoli florets on top, if using.
Sprinkle the remaining cheese across the dish.
In a small bowl, mix breadcrumbs with melted butter, then scatter over the top.
Bake uncovered for 45–50 minutes, or until the chicken is fully cooked and the top is golden and bubbly.
Let it rest for 5 minutes before serving. Trust me, it’s worth the wait.