In a large mixing bowl, mash the bananas. Add sugar, oil, eggs and vanilla. Mix together until thoroughly combined.
Sift flour, baking soda and salt into the banana mixture. Stir until all ingredients are incorporated then mix about ¼ cup of cocoa nibs into banana batter.
Spray the cups of a 12-cup muffin pan with non-stick spray. Pour banana batter into each cup until the cup is almost full. Sprinkle the remaining cocoa nibs on the top of each muffin.
Bake for 15-19 minutes. The muffins are done when they are slightly browned and a toothpick can be inserted into the middle of the muffin and come out clean.