Combine milk, cream, sugar, vanilla, salt and peppermint extract in a large bowl and whisk vigorously until all sugar has been dissolved. Add green food coloring to desired color. Pour mixture into ice cream maker and freeze according to manufacturer's instructions. After about 15 minutes of freezing, add chopped chocolate chips and continue freezing until thickened, about 25-30 more minutes. Spoon ice cream into a container to freeze until firm enough to scoop, about 3-4 hours.