Step by step

Incorporate the egg whites

Tips
To soften the Nutella, and make it easier to spread, you could try putting it into the microwave for a few seconds, or you can melt it in a bain marie - but the water must never boil.
Trivia
Nutella is mentioned in song lyrics: Negrita, in their album XXX, mention it in a song "Sex" where they sing: "try the recipes, try some cooking, use Nutella, use flour."