Preheat your oven to 350°F (about 175°C). Lining your cookie sheets with parchment paper helps prevent sticking and makes for easy cleanup later.
In a mixing bowl, whisk together baking soda, baking powder, and flour. This step ensures that all the leavening agents are evenly distributed throughout the flour.
In another bowl, cream together the softened butter, Nutella, granulated sugar, and brown sugar until the mixture is light and fluffy. This process incorporates air, leading to a lighter cookie.
Add the package of instant chocolate pudding mix to the butter and sugar mixture, beating until well blended. The pudding not only adds flavor but also moisture to the cookies.
Crack in the eggs and add vanilla extract. Beat well until everything is nicely combined.
Slowly add the flour mixture to the wet ingredients, mixing until just combined. Be careful not to overmix, as that can lead to tougher cookies.
Gently fold in the chocolate chips, chopped nuts, and Mallow Bits until evenly distributed throughout the dough.
Using a cookie scoop or your hands, scoop about a tablespoon of dough and roll it into a ball. Place the balls onto the prepared cookie sheets, spaced about two inches apart to allow for spreading during baking.
Bake the cookies in the preheated oven for 9 to 11 minutes. They should appear slightly underbaked in the center but golden around the edges. This ensures they stay soft and chewy.
Once done, remove the cookies from the oven and let them cool on the baking sheets for a couple of minutes before transferring them to a wire rack to cool completely.