Preheat the oven to 350F/180C. Coat a loaf pan with non-stick spray and line with parchment paper. Set aside.
Whisk flour, baking powder and salt in a bowl, set aside.
In a large bowl beat the sugar and olive oil until completely incorporated. Add in mashed bananas, egg, and vanilla. Beat until completely mixed.
Add in flour mixture and mix until incorporated. Fold in zucchini and walnuts.
Pour the batter in the loaf pan, top with chocolate chunks and bake for 45 minutes or until a toothpick inserted in the middle comes our with small crumbs on it.
Let the bread cool completely before slicing it.