Preheat oven to 350 degrees F. Line baking sheets with parchment paper and set aside. Using a stand mixer fitted with the paddle attachment (or a large mixing bowl with a hand mixer), combine the butter, granulated and brown sugars, eggs and vanilla and beat on medium speed until creamy and free of lumps. Add the Nutella and mix until just combined.
In a separate bowl, combine the flour, cocoa powder, baking powder, baking soda and salt. Mix well. Gradually add to the butter mixture and beat on medium speed until just combined. Fold in the chocolate chips and M&M’s.
Using a medium cookie scoop, place 1.5-tablespoon-size chunks of batter 2 inches apart on the prepared baking sheets. Bake in the preheated oven for 9-11 minutes, or until cookies are uniformly puffy and centers are cooked through.