Preheat the oven to 350 degrees F and grease an 8x8-inch pan with nonstick spray.
Add the chickpeas to a colander to drain. Rinse with water. Drain.
Add to a food processor with the banana, peanut butter, maple syrup, vanilla, salt, and baking soda. Grind on high to make a uniformly smooth batter. (It might take 15-30 seconds.)
Pulse in the flour and chocolate until just combined.
Pour batter into the prepared pan and bake for 24-26 minutes, or until the edges are lightly golden brown and the top is firm to the touch.
Let cool fully in the pan and slice to serve.
