Preheat your oven to 350°F (175°C) and line a muffin tin with paper liners or grease it lightly.
In a large bowl, combine the grated zucchini, granulated sugar, brown sugar, vegetable oil, eggs, and vanilla extract. Mix until well combined.
In another bowl, whisk together the all-purpose flour, whole wheat flour, baking soda, baking powder, ground cinnamon, and salt.
Gradually add the dry ingredients to the wet ingredients, stirring until just combined. Be careful not to overmix.
Fold in the chocolate chips and toasted walnuts until evenly distributed.
Divide the batter evenly among the muffin cups, filling each about 2/3 full.
Bake for 20-25 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Allow the muffins to cool in the pan for 5 minutes before transferring them to a wire rack to cool completely.