Preheat oven to 350 degrees. Line muffin tin with liners. Spray liners with nonstick cooking spray.
Combine first 5 ingredients (flour through salt) in a medium bowl. Stir.
Combine next 5 ingredients (egg through milk) in a smaller bowl. Whisk together. Gently stir in zucchini.
Add zucchini mixture to the dry ingredients and stir just until combined. Stir in chocolate chips.
Divide evenly among muffin tins. (I filled them a little over 3/4 of the way full.) Top with a couple chocolate chips, if you want.
Bake for 20 minutes or until toothpick inserted in the middle of the biggest muffin comes out clean. Don't over bake or they get really dry!