2 (6 ounce) packages uncooked long grain and wild rice
2 cups cooked, cubed chicken breast meat
1 (10.75 ounce) can condensed cream of mushroom soup
1 (4 ounce) jar diced pimento peppers, drained
1 cup shredded Cheddar cheese, divided
Preheat oven to 300 degrees F (150 degrees C). Prepare rice according to package directions.
In a medium bowl, toss together the cooked chicken, prepared rice, soup, pimientos, and onion. Transfer to a lightly greased 9x13 inch baking dish. Stir in 1/2 cup of the cheese, then sprinkle the other 1/2 cup of cheese on top.