Preheat oven to 325 degrees. Spray a 9" x 13" baking dish with cooking spray and set aside. Cook long grain and wild rice while continuing with recipe.

Heat large skillet over medium high heat and bring oil to a shimmer. Add chicken and cook stirring occasionally until pink is gone. Remove chicken to plate and add butter. When butter is melted add onion and cook until translucent about 3 minutes.

Scatter flour over butter and onions then cook 1 minute. Pour in milk and bring back to a simmer. Let sauce simmer 3 minutes.

Leave chicken diced or shred into bite-size pieces and place back into pan. Add broccoli and cooked rice then stir in salt and pepper to taste.

Transfer mixture into prepared casserole dish and top with onion rings. (Leave in skillet if it can be placed in the oven.)

Bake 20-25 minutes until hot and bubbly.