In 2-quart saucepan, melt 1/4 cup butter over medium heat. Add flour; cook 1 minute, stirring constantly with whisk. Stir in reserved 1 1/2 cups broth and the whipping cream; heat to boiling, stirring constantly. Stir in salt, pepper and nutmeg. Remove from heat; add Swiss cheese. Stir until cheese is melted and sauce is smooth.