In large bowl or stand mixer with whisk attachment, beat eggs for about 4 minutes, or until light colored and thickened. Then, beat in sugar.
Heat 1 cup of heavy cream in a medium sized sauce pot over medium heat. Once cream is hot, slowly pour a little over half of the cream into the egg yolk mixture, stirring continuously (it is important to do it slowly, and stir, so that you do not cook the eggs). Then, pour the mixture back into the remaining heavy cream in the pot, still stirring continuously.
Turn heat under pot to low, and stir continuously until mixture begins to thicken, about 5 minutes. After mixture has thickened, remove from heat and whisk in chocolate chips and Nutella until smooth.
Place the egg mixture in a bowl in the refrigerator for at least two hours.
After mixture has chilled, beat remaining 1 cup of whipping cream with whisk attachment until stiff peaks form, about 5 minutes.
Fold whipped cream into chocolate/egg mixture until well combined.