Add the avocado, coconut milk, maple syrup, and peppermint extract to a blender and blend until smooth. Taste, and adjust any flavoring as needed. You can add more maple syrup to make it sweeter, or more peppermint if you have a particulary strong-flavored avocado.
Pour the mixture into an ice cream maker and run the machine according to the manufacturer directions. It takes about 20 to 25 minutes to become thick and creamy. Alternatively, you can skip the machine and pour the mixture into a loaf pan to freeze for 4 to 6 hours, until firm.
When the ice cream is thick and frozen, stir in the cacao nibs, if desired. (You can also use mini chocolate chips, if you prefer.) I let the ice cream maker run for 2 more minutes to stir them in, or you can simply stir them into the loaf pan 2 hours after it's been starting to freeze.
Serve frozen right away from the ice cream maker, or store it in an airtight container in the freezer until ready to serve. This ice cream is the most "scoopable" the same day you make it, but it is still relatively easy to scoop the next day compared to other homemade vegan ice creams. Let it sit on the counter for 10 minutes, if you need to help it soften up before serving. Store in the freezer for up to 2 months, in an airtight container so the avocado isn't exposed to oxygen and won't brown.
Nutrition information is for 1 of 6 servings, roughly 1/2 cup. This is automatically calculated and just an estimate, not a guarantee.