While an ice cream maker yields the best results, you can still make a no-churn version of chunky monkey ice cream. Combine the mashed bananas, heavy cream, whole milk, sugar, and vanilla extract in a bowl. Whip them together until well combined and slightly thickened. Then, fold in the chopped walnuts and chocolate chips. Transfer the mixture to a freezer-safe container and freeze for several hours, stirring every 30 minutes to break up ice crystals until it reaches the desired consistency.