Using a blender, add two scoops of vanilla ice cream to the blender. Whole milk ice cream with a high butter fat content tastes and blends the best. Add one scoop of the pumpkin pie mix to the blender. Next, add 1/4 cup crushed Nilla wafers to the blender. Do not crush them finely, only barely crushed into big chunks in your hand. Blend the ingredients on a pulse setting for 20 seconds. Do not over blend. Scoop the contents into a glass and top with a dollop of cool whip and a sprinkle of nutmeg.