Crush the Nilla Wafers using a mini food processor or by placing them in a large zip lock bag and rolling over them with a pin.
In a medium bowl, mix the crushed Nilla Wafers with melted butter.
Press the mixture into the bottom of a 9×9-inch pan (for thicker bars) or a 9×13-inch pan lined with parchment paper.
Chill the crust in the refrigerator or freezer while you prepare the filling.
Place a large metal bowl in the freezer for about 10 minutes to chill.
Using an electric mixer on medium speed, whip the heavy cream and sugar until stiff peaks form and set aside.
In another large bowl, beat the softened cream cheese with an electric mixer on medium speed until smooth.
Gradually add the dry pudding mixes, beating well after each addition.
Fold in the whipped cream until the mixture is smooth.
Spread the cheesecake filling evenly over the chilled crust.
Cover with plastic wrap and refrigerate for at least 8 hours, or overnight.
Once chilled, cut the cheesecake into squares and, if desired, top with whipped cream and banana slices.
Serve cold.