Preheat your oven to 350°F (175°C) and prepare a 9x5-inch loaf pan.
Wash and grate the zucchinis, then squeeze out excess moisture.
In a large bowl, mix the dry ingredients: flour, baking soda, baking powder, salt, cinnamon, and nutmeg.
In another bowl, whisk together the sugars, oil, eggs, and vanilla until smooth.
Gradually add the dry ingredients to the wet mixture and stir until just combined. Fold in nuts or chocolate chips if desired.
Pour the batter into the prepared loaf pan and smooth the top.
Bake for 50-60 minutes, checking for doneness with a toothpick.
Allow the bread to cool in the pan for about 10 minutes before transferring to a wire rack.