Preheat the oven to 350 degrees F. Lightly grease a 9x5-inch loaf pan with nonstick spray. Line with parchment paper so that the paper overhangs two sides like handles, then lightly grease again.
Thoroughly squeeze the shredded zucchini with a paper towel to remove as much excess water as possible. Repeat as needed.
In the bowl of a standing mixer or a large mixing bowl, beat the mashed banana with the honey, coconut sugar, coconut oil, and vanilla extract until smooth. (You can also use a whisk and some elbow grease and mix the batter by hand.) Add the eggs (make sure they are room temperature or the coconut oil may resolidify), then mix again until smoothly combined. If the coconut oil does resolidify, microwave the bowl in 10-second bursts, just until the coconut oil reliquifies.
Sprinkle the cinnamon, nutmeg, baking soda, baking powder, and salt over the top of the batter. Mix to combine. Sprinkle the flour evenly over the top, then mix on very low speed, just until the flour disappears. By hand, fold in the zucchini and the nuts or chocolate chips (if using), stopping as soon as it's mostly evenly blended. Do not overmix. The batter will be thick.
Scrape the batter into the prepared pan and smooth the top. Bake for 50 to 60 minutes, until a thin, sharp knife such as a paring knife inserted in the center comes out clean two tests in a row. (You want to test for a clean knife more than once, as moist quick breads can be tricky to tell; if in doubt, take the bread's temperature on an instant-read thermometer. It's done when it reaches 195 degrees F.). I like to check the bread at the 30-minute mark and tent it with foil if the bread is browning too quickly at the corners, then continue baking as directed.
Once the bread is baked, place the pan on a wire rack and let cool for 15 minutes. Lift the bread from the pan using the parchment paper, and place the loaf on the rack to finish cooling completely. Slice and enjoy!