Line a tray that can fit in your freezer with parchment paper.
Slice the bananas into coins and place in rows on the tray. Place another sheet of parchment paper on top and use a cup to lightly flatten. Remove the top sheet of paper.
Pour nut/seed butter on top of the banana coins, spread evenly.
Melt chocolate by placing chocolate chips and coconut oil in a bowl and microwave for 30 seconds, stir, repeat, until smooth. Pour on top of banana and nut butter and spread evenly.
Place in the freezer for about an hour or until firm and set.