Remove stalks and tough stems from Swiss chard. Wash thoroughly, and tear into large pieces.
Place Swiss chard in a large Dutch oven (do not add water). Cover and cook over medium heat 4 to 6 minutes or until tender. Drain; place on paper towels, and squeeze until barely moist. Return Swiss chard to Dutch oven.
Melt butter in a small saucepan over low heat; add flour, and stir until smooth. Add to Swiss chard, stirring well. Add whipping cream; cook over low heat 15 minutes or until mixture is slightly thickened, stirring occasionally. Add salt, pepper, and ground nutmeg; stir well. Serve immediately.