Microwave butter, marshmallows, and brown sugar for 2 1/2 min.
Remove from microwave and stir until smooth. Add in Nutella, stir until smooth.
Return to microwave and microwave for one more minute. Stir until smooth
Pour over popcorn in a large bowl. Stir until popcorn is covered with mixture.
Spread on a large baking sheet and allow to set up
Notes
For a less gooier version, use half the amount of marshmallows.To use the stovetop instead of the microwave, melt the butter, marshmallows and brown sugar in a saucepan on the stove top over medium heat. Then add in the Nutella and stir until melted and combined.Leftover Nutella popcorn can be stored in an airtight container and it will last 2-3 days.