Preheat oven to 350°F.
With a sharp knife, make deep lengthwise cut along inside curve of each banana, being careful not to cut all the way through. Open the banana so you can fill easily. Crimp and shape 1 sheet of foil around each banana, forming boats. Add nut, fruit and cereal mix. Return each banana to its foil boat. Seal top of foil loosely around the banana, leaving a couple inches of space. Bake 15-20 minutes in oven until bananas are warm.