Add the eggnog, milk, vanilla syrup, and nutmeg to a small saucepan and stir to combine. Heat over medium heat until the eggnog mixture starts to bubble on the edges. Remove from heat.
Froth the eggnog mixture until foamy and set aside.
Brew your espresso and pour into a coffee mug.
Top with the frothed eggnog mixture. Sprinkle with nutmeg and/or top with whipped cream. Drink up!