In a medium bowl, whisk together chocolate milk and sweetened condensed milk until combined.
Pour this mixture into the ice cream maker bowl and freeze according to your ice cream maker's directions. (I turn my ice cream maker on before pouring. This helps to prevent the liquid from sticking to the sides right away.)
Once it reaches the consistency of a frosty, its ready to serve. It took about 25 minutes in mine.
Video
Notes
I have a 1 ½ quart ice cream maker and this recipe works perfectly for this size. If your ice cream maker is larger, you may want to double the recipe.
Also, the ice cream maker bowl must be completely frozen before use. I cover it with plastic wrap (so it doesn’t form ice crystals on the bowl) and freeze for at least 24-48 hours. When I’m ready to use it, I pull off plastic wrap, pop it into position and turn it on.
Freeze any leftovers in an airtight container for up to two weeks.
If you don't have an ice cream maker, just whisk together the two ingredients in a freezer-safe bowl, cover and stick into the freezer for several hours until it starts to get slushy. Stir again. Once it reaches the consistency of a frosty, then its ready to enjoy!