Prepare your pudding according to the package directions, using the 1 ½ cups nonfat milk.
Fit a disposable pasty bag with a round decorating tip (#230) and fill the bag with the pudding. Place the tip into the center of the top of the cupcake and fill. Alternately, you can cut a small hole in the top of the cupcake and add a spoonful of pudding.
Frost the tops with the chocolate icing. Note: the sugar-free icing is very thick. I recommend using a warmed knife to frost the cupcakes instead of using a pastry bag.