Combine the flour, baking powder, and salt in a medium bowl; set aside. With an electric mixer on medium-high speed, beat the Nutella, butter, and granulated sugar until light and fluffy, about 2 minutes. Add the eggs, vanilla, and espresso powder and mix until incorporated. Reduce the speed to low and alternate additions of flour mixture and milk, starting and ending with the flour, and mixing until just combined after each addition. Fold in ½ cup of the hazelnuts. Refrigerate the dough until firm, at least 2 hours and up to 24 hours.