Brew the coffee. Stir the espresso powder into the hot water and set aside.
Mix the eggnog mixture. In a glass measuring cup combine milk, eggnog, vanilla, brown sugar, cinnamon, and nutmeg. Whisk until thoroughly combined.
Make it frothy. Heat the eggnog mixture in the microwave for 1 minute and 30 seconds, or until the milk starts to froth up. Stir, and return the mixture to the microwave for an additional 30 seconds, or until the milk froths up again.
Combine. Remove the eggnog mixture from the microwave and slowly add the brewed coffee, stirring constantly.
Serve. Top your eggnog latte with whipped cream, dust with nutmeg, and enjoy!