Preheat oven to 350°
Lightly grease two 8x4 or 9x5 loaf pans with cooking spray, baking spray, butter, or shortening.
In a large paper plate or medium bowl, whisk together flour, sugars, cocoa, baking soda, baking powder, and salt. I like to use a large, rimmed paper plate for the dry ingredients so I only have to wash one bowl.
Whisk eggs or stir with a fork in a large bowl. No mixer needed for this recipe.
Press zucchini between paper towels to pat dry, then add to the eggs in the bowl. Add Nutella, oil and vanilla and stir well. Add mini chocolate chips and stir well.
Add dry ingredients to the zucchini mixture and stir until dry ingredients are moistened. Spoon batter into the prepared 8x4-inch loaf pans or two 9x5 loafpans. Bake for 45 minutes for the 8x4 loaf pans and 40 to 45 minutes for the 9x5 pans or until a toothpick inserted in the center comes out almost clean. Let cool 15 minutes in the pan on a wire rack.
Remove bread from pan and let cool completely on a wire rack.