Preheat oven to 350°F.
Line a regular (not a mini) 12 cup muffin tin with paper liners.
Mix together eggs and Nutella in a medium bowl until smooth. Add in flour and mix until just combined.
Evenly spread into prepared muffin cups. Sprinkle each with a few chocolate chips, if desired.
Bake 12 minutes.
Note: If you microwave the Nutella for a few seconds, it will soften it and allow for easier mixing.