Chocolate chips are used frequently in many desserts especially cookies. However, for those who are vegan, not all chocolate chips are for vegans. So, you really must read the package to search for certain ingredients to see if they are considered to be vegan or not. If the product has milk or any type of milk product, then it is not vegan.
Even nonfat milk would not be considered vegan. Some chocolate chips like those generic versions at Walmart are made for vegans. Semi-sweet and bitter-sweet chocolate may not have any milk products. Other chocolate chips may contain animal products which would make this product not considered to be vegan. Most Nestle products contain milk or animal products which make them not for vegans.