Drain pineapple, reserving juice; set pineapple aside. In a saucepan, combine the sugar, cornstarch, eggs and reserved juice; mix well. Cook and stir until a thermometer reads 160°. Remove from the heat. Pour into a bowl; cool completely.
In a small bowl, beat cream until stiff peaks form. Fold into cooled egg mixture. Add marshmallows and reserved pineapple. Cover and refrigerate for 4 hours. Just before serving, fold in bananas and nuts.