This works with any spice. Try allspice for a little more kick.
This also presumes you are drinking eggnog properly, meaning with bourbon or rum. Presuming you only drink real eggnog because the common knockoffs are intolerable, why would you drink uncooked eggs without some booze to kill the bacteria?
So the trick is to add the liquor to your glass, then add the spice, stir if necessary, then add the eggnog, and stir again. Spices disburse in liquor but not in eggnog.
The Final Product: Spice Evenly Distributed Throughout the Beverage Without Clumps