Cook pie shell according to instructions.
Remove label from can. Place unopened can of Eagle Brand milk in saucepan; completely cover the can with water.
Boil 3 hours, replacing water when needed. Keep can COMPLETELY submerged in boiling water at all times. After 3 hours boiling, cool can completely (approximately 4 hours).
Sprinkle 1/4 cup chopped walnuts on the crust.
Slice bananas and place in a layer on the top of the crust.
Carefully open cooled can of sweetened condensed milk and pour into pre-cooked pie shell. Refrigerate for at least 1 hour.
Top with Cool Whip and 1/4 cup chopped walnuts.