In a large pot, cook the noodles according to the package directions.

Cook broccoli.

Drain noodle water, reserving 1/2 c. liquid to mix in casserole.

Using a saucepan, prepare white sauce by heating 3 T. butter then whisk in 1/4 c. flour for about a minute. Gradually add 2 c. milk. Heat and stir until thickened and no longer lumpy.

Add the chicken, broccoli, sauce, water or milk, sour cream, and onion powder to the large pot with noodles. Mix well until everything is coated. Pour into a 9 x 13 pan and sprinkle with cheeese on top. Put under the broiler until cheese is melted.

Serve warm with bread.