Stop the mixer and add in the mashed bananas, lemon juice and the bourbon. Turn the mixer back on and beat until the ingredients are incorporated. With the mixer on low, add the entire flour mixture. Beat until mostly incorporated. Turn the mixer off, and then fold in the walnuts and chocolate chips. Make sure ingredients are folded in and ingredients are mixed (i.e. you don’t see any more white flour particles). The batter will be rather thick.