Preheat oven to 350 degrees. Line an 8x8 square pan with parchment paper.
In a large bowl, add the banana and mash until smooth. Then add the shredded zucchini, tahini, maple syrup, milk, and vanilla. Stir with a spatula until well combined.
Add the oats, cinnamon, nutmeg, ground flaxseed, baking powder, and salt. Stir until well combined. Fold in chocolate chips, saving a few for the top.
Pour batter into the prepared pan. Sprinkle some chocolate chips on top. Bake for 40 minutes, or until top is set and golden. Sprinkle some flaky sea salt on top. Let it cool for 20 minutes. Enjoy warm with a drizzle of tahini or nut butter, coconut yogurt, or a drizzle of pure maple syrup if you want it a little sweeter.
Store leftovers in an airtight container in the fridge for up to 5 days or in the freezer. You can reheat it in the microwave or toaster oven before eating.