Preheat the oven to 350°F.
Line a 12-cup cupcake pan with cupcake liners.
In a large mixing bowl, whisk the sugar, butter, and oil until combined.
Add the eggnog, eggs, and vanilla and whisk until combined.
In another bowl, mix together the flour, baking powder, nutmeg, and salt.
Add the dry mixture to the wet mix in 2 batches, mixing just until smooth after each batch. Scrape down the sides of the bowl as needed.
Divide the batter evenly into the liners, filling each to about 2/3 full.
Bake for 20 minutes, or until a toothpick inserted in the center of a cupcake comes out clean.
Allow the cupcakes to cool to room temperature.