Mix Nutella and 1/2 cup softened butter together in a stand mixer. Beat until smooth and creamy. Add in sugar and vanilla. Beat on medium until mixture is combined and smooth.

Line 8x8" pan with wax paper. Press Nutella mixture down evenly in the pan

Melt chocolate chips in microwave safe bowl, slowly (30 seconds at a time to not burn) when chocolate is almost melted add in softened tablespoon of butter. Mixture should be smooth

Spread chocolate over top of Nutella mixture.

Allow fudge to set in refrigerator for approx. 10 minutes. Remove from fridge and while fudge is still slightly soft cut into desired size pieces.

Cover the sliced fudge and return to fridge to set. Store in an airtight container.