Preheat oven to 350 F. Line or grease a 8x4 inch loaf pan.
Into a large bowl, mash banana until smooth. If you prefer a banana bread with a smoother crumb, blend the banana and then add to the bowl. Add nut butter, maple syrup, non dairy milk, vanilla extract, apple cider vinegar and whisk until well combined. Add in the cassava flour, almond flour, coconut flour, baking powder, baking soda and salt and whisk until just combined. Use a spatula and fold in chocolate chunks.
Transfer to prepared loaf pan and bake for 45-50 minutes or until toothpick inserted in the middle of the loaf comes out clean (few cooked crumbs are okay). Allow the loaf to cook in the pan for 3 minutes and then transfer to a wire rack. Cool for 1 hour, slice & enjoy!