Preheat oven to 350 degrees F and spray an 8x4 inch loaf pan with nonstick cooking spray.
In the bowl of an electric mixer, combine bananas, Greek yogurt and egg. Beat on medium speed until smooth. Add sugar, vanilla extract and coconut oil and beat again until combined and creamy.
In a separate bowl, combine chickpea flour, baking powder, baking soda, cinnamon and salt and whisk until combined.
Slowly pour dry ingredients into wet and use a wire whisk to mix until just combined. Fold in chocolate chips and walnuts.
Pour batter into prepared pan and smooth top. Bake for 45-55 minutes or until tester inserted into center comes out clean. Remove from oven and place on wire rack to cool for 30 minutes, then carefully invert, remove bread from pan and place back on wire rack to cool completely. Cut into 12 slices.