Preheat your oven to 350 degrees F. Get a 12-cup muffin tin ready by either lining it with paper liners or greasing it. Set aside.

In a large bowl, combine the flour, sugar, baking soda, cinnamon, and salt. Mix well.

In another container, whisk together the oil, buttermilk, and vanilla extract. Pour this into the dry ingredients and stir just until the mixture starts to come together. It's okay if some flour is still visible.

Fold in the shredded zucchini. The moisture from the zucchini will help incorporate the remaining dry ingredients. Be careful not to over mix.

Gently stir in the mini chocolate chips and chopped walnuts.

Divide the batter evenly among the 12 muffin cups.

Bake for 20 to 25 minutes, or until a toothpick inserted in the center comes out clean. Let the muffins cool in the tin for a couple of minutes before transferring them to a wire rack to cool completely.