In a medium saucepan, combine the milk and eggnog over medium heat. Stir gently and consistently until the mixture is warm to the touch but ensure it doesn't reach boiling point.
Once the milk and eggnog blend is warm, introduce the chopped white chocolate into the saucepan. Stir continuously until the chocolate is completely melted and the mixture achieves a velvety smooth texture.
After the chocolate has melted, mix in the vanilla extract and the 1/4 teaspoon of grated nutmeg, stirring well to ensure all ingredients are incorporated. Taste the luxurious hot chocolate and adjust the sweetness or spice according to your preference.
Carefully remove the saucepan from the heat and allow the hot chocolate to cool for a minute, making it comfortable to serve.
Pour the rich eggnog white hot chocolate into mugs, leaving a little space at the top to accommodate the whipped cream.
Generously dollop whipped cream on top of each mug, creating a delicious layer of creaminess.
For the finishing touch, lightly sprinkle a pinch of additional nutmeg over the whipped cream. If desired, add a cinnamon stick for an added festive flair and aromatic experience.