Preheat oven to 350 degrees F. Line baking sheet with parchment and set aside.
In a medium saucepan over medium heat, combine the peanut butter, Nutella, and butter. When the butters have melted together and are smooth, remove from heat and transfer to a mixing bowl. Add the sugar, vanilla, and salt. Mix until the sugar is dissolved, then mix the cocoa powder and egg. When combined, then add the flour and mix until almost all of the flour is gone. Add the chocolate chips and stir until just distributed.
Divide the cookie dough into 12 balls and place 6 on a large cookie sheet at least 2 inches apart. Use a fork to gently press the balls down in a cross hatch pattern, then sprinkle with a pinch of flake salt. Place on the center rack and bake for 10-12 minutes. Repeat for remaining cookies.
When the cookies are baked, remove from the oven and tap on the counter 2-3 times to eliminate air bubbles.
Slide the parchment onto a cooling rack and allow to cool completely before enjoying!