Peel the bananas and cut them into 1-inch chunks. Place the chunks on a parchment lined baking sheet, cover, and place in the freezer for 6 hours or until frozen.
Put the frozen banana pieces into a large food processor. Add the cocoa powder, maple syrup, and 3 tablespoons of cacao nibs.
Turn the food processor on and blend for 3-5 minutes, stopping the processing several times to stir the mixture. It will start to loosen up after the first 2 minutes. The cacao nibs will remain crunchy.
Garnish the ice cream with 2 teaspoons of cacao nibs and serve. Store leftovers in the freezer.