Preheat your oven to 350°F (175°C). Grease the loaf pan with non-stick spray or butter.
Grate the zucchini using a grater. Place it in a clean kitchen towel and squeeze out any excess moisture.
In a large mixing bowl, combine the grated zucchini, granulated sugar, brown sugar, and vegetable oil. Mix well.
Add the eggs and vanilla extract to the bowl and whisk until smooth.
In another bowl, mix together the flour, baking soda, baking powder, salt, and ground cinnamon.
Gradually add the dry ingredients to the wet ingredients, stirring gently until just combined. Avoid overmixing.
If desired, fold in the chopped walnuts or pecans.
Pour the batter into the prepared loaf pan and smooth the top.
Bake in the preheated oven for about 50 minutes or until a toothpick inserted in the center of the bread comes out clean.
Once done, remove from the oven and let the bread cool in the pan for about 10 minutes before transferring to a wire rack to cool completely.