Preheat your oven to 350°F (175°C). Grease and flour a 9x5-inch loaf pan or line it with parchment paper.
In a large bowl, combine the grated zucchini, flour, baking soda, baking powder, salt, cinnamon, and nutmeg. Mix well and set aside.
In another bowl, whisk together the granulated sugar, brown sugar, vegetable oil, eggs, vanilla extract, lemon zest, and lemon juice until smooth.
Gradually add the wet ingredients to the dry ingredients, stirring until just combined. Do not overmix; a few lumps are okay.
Pour the batter into the prepared loaf pan and smooth the top. Bake for 50-60 minutes or until a toothpick inserted in the center comes out clean.
Once baked, remove the bread from the oven and let it cool in the pan for about 10 minutes. Then transfer it to a wire rack to cool completely.
For the glaze, whisk together the powdered sugar, lemon juice, and lemon zest in a small bowl until smooth. Drizzle the glaze over the cooled bread.