In a large mixer bowl, combine cake mix, eggnog, water, butter eggs and nutmeg. Beat at medium speed with an electric mixer 2 minutes. Pour batter into a well greased and floured 10-inch Bundt pan. Bake at 350 degrees for about 50 minutes or until cake is golden brown and comes away slightly from edge of pan. Transfer to a wire cooling rack; let stand 10 minutes. Invert cake onto rack and cool completely.
For glaze, combine powdered sugar, melted butter and hot milk; mix until smooth. Place cooled cake on serving platter. While still warm, spoon glaze over cake, letting excess drip down sides of cake; sprinkle with nutmeg. Let stand until glaze is set, about 10 minutes. Serve with sweetened whipped cream if desired.