Make batter: Add zucchini, oil, honey, Greek yogurt, eggs and vanilla to a large mixing bowl and stir until well combined. Combine flour, cornstarch, baking powder, baking soda, salt, cinnamon and nutmeg (if usinin a separate medium bowl and stir until combined. Add wet to dry ingredients and fold together just until combined – do not overmix, a few lumps are fine! Fold in the chocolate chunks.