In a large frying or saute pan over medium heat, melt the butter.
Add the flour and dry seasonings - garlic powder, onion powder, salt and black pepper.
Stir and cook for 1-2 minutes until a paste forms and it is fragrant.
Add the chopped green pepper, drained mushrooms and drained pimentos. Stir well and cover the pan. Allow to cook for 4-5 minutes, stirring occasionally.
Stir in the chicken broth, scraping up any browned bits in the bottom of the pan. Simmer and stir until the sauce thickens.
Add the chopped rotisserie chicken. Stir well to combine and cover with a lid. Allow the sauce to simmer on low while you prepare the noodles.
When ready to serve, add the Worcestershire sauce and sour cream. Stir until smooth and allow to simmer until the sauce is warmed through.
Serve the chicken a la king with cooked and buttered egg noodles.