Preheat the oven to 350℉. Lightly grease a 9x13 inch baking pan and set aside.
In a medium bowl, mix together the cake mix, water, oil and eggs.
Pour the batter into the prepared baking pan and bake in the preheated oven for 35 minutes. Allow to cool completely.
Line a baking sheet with parchment paper. Set aside.
Mix together the cooled cake and Nutella until combined.
Using a medium cookie scoop, scoop the cake mixture into your hands. Smooth it into a ball and place on the prepared baking sheet. Repeat for the remaining cake mixture.
In a small microwave safe bowl, microwave the white chocolate chips and the coconut oil in 30 second intervals, mixing until smooth.
Dip the cake balls into the melted white chocolate, then return to the baking sheet. Repeat for all of the cake balls.
Drizzle with more melted Nutella, if desired.
Notes
Store in the fridge for up to 4 days, or in the freezer for up to 3 months.