Pour the eggnog into a large pitcher or small punch bowl.
Add the Fireball, pumpkin pie spice, and ground cinnamon. Stir to combine. (I recommend a whisk or immersion blender to fully incorporate the spices.)
Pour the punch into serving glasses and add a scoop of vanilla ice cream. Top with some freshly ground nutmeg and serve immediately.
Notes
Nutritional information includes 4.25 ounces of eggnog with 2 tablespoons of vanilla ice cream per drink.
The addition of ice cream turns this eggnog into a sort of holiday "sherbet" punch. The ice cream can be added to the punch bowl instead of glasses if you prefer.
If making this punch ahead of time, be sure to stir it well before serving as the spices can settle to the bottom of the pitcher/bowl.
Store leftovers, covered with plastic wrap, in the fridge for up to 1 week.