Preheat oven to 180 C. Line a metal 9x9 pan with parchment paper.

Pour melted butter into a bowl. Whisk in sugar by hand until smooth, 30 seconds.

Add in eggs and vanilla extract. Whisk 1 minute.

Whisk in Nutella until combined and smooth

Stir in flour, cocoa powder, and salt until just combined. Add in chocolate chips.

Pour into prepared pan and smooth out.

Bake in the preheated oven for 30 minutes. Let cool in pan 30 minutes before slicing.