Preheat oven to 180°C. Coat a 23 x 13cm loaf pan or a 20cm x 20cm baking pan with cooking spray. Set aside.
Sift the flour, cocoa powder, baking soda, baking powder, cinnamon, nutmeg and salt into a large bowl.
In another bowl, whisk together the coconut sugar, oil, yoghurt, maple syrup, eggs and extract. Add the wet ingredients to the flour mixture and stir until just combined (with a few traces of flour still present). Add the zucchini and chocolate chips and stir to combine.
Spoon the batter into the prepared baking pan and flatten the top with a rubber spatula. Bake until a toothpick inserted into the centre of the bread comes out clean, about 45 minutes for a loaf pan and 30 minutes for a 20cm x 20cm baking pan.
Cool in the pan for 10 minutes. Run a knife around the edges of the pan and invert onto a cooling rack.
Wrap leftovers tightly and store at room temperature for up to four days.