Preheat oven to 350 degrees. Line a twelve tin muffin pan with liners.
In a large bowl mix together flour, baking powder, baking soda, and salt.
In a smaller bowl, beat together sugar, ½ cup oil, eggs, buttermilk, orange juice and zest.
Make a well in the dry ingredients and slowly mix in the wet ingredients until well combined. Do not overmix. Add I cup of the chocolate chips. Reserve ¼ cup for drizzle.
Fill the muffin cups evenly with the batter.
Bake for 18 to 22 minutes or until muffins are golden and toothpick stuck in the center comes out clean.
Cool for 10 minutes before moving to a baking rack.
In a small bowl mix together ¼ cup reserved chocolate chips and ½ teaspoon reserved canola oil. Melt in microwave at 30 second increments until smooth. Drizzle chocolate over muffins.