Preheat the oven to 350°F. Grease a 9x13-inch casserole dish, set aside.

In a skillet, melt the butter over medium heat. Sauté the Rice-A-Roni (without seasoning) and diced onions until the rice is lightly golden, about 3-4 minutes.

In a large mixing bowl, combine the sautéed Rice-A-Roni, seasoning packet from the box, shredded chicken, French onion soup, cream of chicken soup, water, sour cream, garlic powder, salt, and pepper. Stir until everything is well combined.

Pour the mixture into the prepared casserole dish and spread it evenly. Sprinkle the shredded cheese on top.

Cover the casserole dish tightly with foil and bake for 45-50 minutes, or until the rice is fully cooked and tender.

Remove the aluminum foil and sprinkle with French fried onions. Bake uncovered for an additional 5-7 minutes, until the onions are golden and crispy.

Let the casserole sit for a few minutes before serving. Garnish with chopped parsley if you like.