In a bowl, combine sweetened condensed milk, ice cold water, vanilla instant pudding mix and salt. Mix together until well combined. Cover and transfer to the refrigerator for at least 4 hours or overnight to allow the pudding to set.
In a large bowl, add heavy cream and whip until stiff peaks form. Fold in 1/3 of the whipped cream into the pudding mixture then pour the pudding mixture into the remaining whipped cream. Gently fold together until there are no visible streaks.
To assemble in a 4 quart glass or trifle bowl, add 1/4 of the pudding mixture. Then layer on 1/3 of the Nilla wafers followed by 1/3 of the sliced bananas. Repeat two more times. You should be left with 1/4 of the pudding mixture which you will layer on top. Garnish with Nilla wafers, Nilla wafer crumbs, and sliced bananas.
Cover and refrigerate for at least 8 hours. Serve chilled and enjoy!
