Preheat the oven to 350°F (180°C), or 160°C for a fan oven. Line a 9×5 inch (approx. 23×13 cm) loaf pan with parchment paper.
Mix eggs, pumpkin puree, sugar, and oil in a mixing bowl.
In the same bowl, add the flour, pumpkin spice, baking soda, baking powder, salt, and vinegar until just combined. Do not overmix the batter.
Gently fold in shredded zucchini and ⅓ cup of chocolate chips.
Transfer the batter to the prepared loaf pan. If desired, sprinkle an additional ¼ cup of chocolate chips on top.
Place the loaf pan in the oven and bake for approximately 55-65 minutes, or until a toothpick inserted in the center comes out clean or with a few moist crumbs.
Let the bread cool in the pan for about 10 minutes, then remove it to cool completely on a wire rack.