In a large mixing bowl, combine the instant vanilla pudding mix and the undrained crushed pineapple. Whisk together until well blended, ensuring there are no lumps.

Fold in the whipped topping gently until the mixture is smooth and creamy.

Add the chopped strawberries, mini marshmallows, halved maraschino cherries, and chopped nuts to the bowl. Stir carefully to incorporate all the ingredients without breaking the fruit.

Finally, gently fold in the sliced bananas to preserve their shape and freshness.

Transfer the Banana Split Fluff mixture into a serving dish or individual cups. Cover with plastic wrap and refrigerate for at least one hour to allow the flavors to meld.

Before serving, garnish with additional fruit or nuts if desired. Serve chilled and enjoy the creamy, fruity goodness!