Preheat oven to 350 degrees F. and line 12 muffin cups with liners (foil liners recommended). If using paper liners, spray liners lightly with cooking spray before filling with batter. You can also spray your muffin tin generously with cooking spray if you prefer to not use liners. I've done both options.
In a large mixing bowl, beat sour cream oil, eggs and vanilla until well combined. Stir in pumpkin, cinnamon and pumpkin pie spice. Slowly add flour, sugar, baking soda, salt and chocolate chips, stirring until well combined. Fill liners 1/2 full with batter.
Place sugar and cinnamon into a small bowl, stirring to combine. With a small spoon, sprinkle tops of muffins with cinnamon sugar mixture. About 1/4 teaspoon each muffin. Bake for 22-25 minutes or until baked through, test with a toothpick to make sure it comes out clean. Remove and let cool. Serve room temperature.