In a large bowl, whisk together instant vanilla pudding mix and cold whole milk for about 2 minutes until smooth, then set aside for 5 minutes to thicken.
In a separate chilled mixing bowl, beat heavy whipping cream, powdered sugar, and vanilla extract until soft to medium peaks form.
To assemble, line clear 12 oz cups with sliced bananas, then layer with vanilla pudding, mini Nilla wafers, and whipped cream. Finish with whipped cream, crushed wafers, and a banana slice on top.