In a large mixing bowl mix combine both boxes of instant vanilla pudding and mix with cold milk.
Use an electric hand mixer to beat until smooth and thickened.
Next, add the sour cream and continue mixing until it is well combined.
Gently fold in the thawed Cool Whip.
Assemble the pudding in a large trifle dish (or a 9x13" glass pan), by lining the bottom with vanilla wafers.
Slice the bananas and layer them on top of the wafers.
Spread a layer of the pudding mixture over the bananas
Repeat the layers. Wafers, bananas, pudding, until you reach the top.
Finish it off by sprinkling crushed Nilla Wafers on top. Chill in the refrigerator for at least two hours.
Right before serving, you can garnish with a few extra banana slices and more crushed wafers for that perfect finishing touch.