Line an 8x8-inch pan with parchment and spray lightly with nonstick spray.

In a medium saucepan, combine Nutella and sweetened condensed milk over low heat, stirring until smooth.

Remove from heat, stir in chocolate chips until fully melted and glossy.

Pour mixture into prepared pan, smooth top, and refrigerate until firm, about 2 hours.

Lift parchment and cut into squares. Store in an airtight container in the fridge.