Preheat oven to 350 degrees and line an 8x8-inch pan with parchment paper.
Add the banana and avocado to a food processor and blend till smooth.
Add the nut butter and blend again to incorporate.
Add the maple syrup, cocoa powder and baking soda. Blend again.
Pour the batter into a medium bowl and stir in chocolate chips.
Pour the batter into the prepared baking dish. Bake 30-35 minutes, or until the center is set and a toothpick or small knife inserted into the center comes out clean. Cool.
To make the glaze, whisk the coconut oil, cocoa powder and maple syrup together in a small bowl. Drizzle over cooled brownies.