Mine is similar. In a large glass baking dish, layer cooked white rice, broccoli, and cooked chicken. Pour 2 cups of sauce (below) over, then top with grated cheddar. Bake for 30 minutes.
Sauce: Melt 4 Tb butter, whisk in 4 Tb flour. Gradually add 2 C water. Raise heat to mdm high. Stir till thick. Add 1 cube Knorr vegetarian bouillon.
Sometimes I add sauteed mushrooms, but it's good without, too.