Preheat your oven to 350°F (175°C) and grease a 9×13-inch baking dish.
Cook the Rice-A-Roni according to the package directions and transfer it to a large mixing bowl.
Stir the cream of onion soup and sour cream into the cooked rice until fully combined.
Fold in the shredded chicken, making sure it’s evenly distributed throughout the rice mixture.
Spread the mixture evenly into the prepared baking dish.
Sprinkle the shredded cheddar cheese over the top.
Bake for 40 minutes, until the casserole is hot and the cheese is melted and bubbly.
Remove from the oven and let the casserole cool for 5 minutes.
If desired, garnish with French fried onions before serving for extra crunch and flavor.
Enjoy!
