In a large mixing bowl with a hand-held mixer, beat the pudding mix with eggnog for 2 minutes. The pudding mixture should thicken slightly. Gently fold in 1 cup of whipped topping until just combined. Spoon the mixture into the pie crust.
Refrigerate the pie for at least four hours.
To serve, place a dollop of whipped topping and a sprinkle of nutmeg on each serving.
