In a medium saucepan, combine undrained pineapple and sugar; heat to boiling. Stir in gelatin until dissolved. Stir in cream cheese until melted and well combined. Remove from heat. Transfer to a large mixing bowl.
Chill about 1 hour or until mixture is slightly thickened. Stir in chopped apple and nuts. Fold in dessert topping. Transfer mixture to a 2-quart baking dish or 1-1/2-quart bowl or mold. Cover and chill at least 4 hours. To serve, cut into squares, serve in bowl, or unmold onto serving plate. If desired, garnish individual servings with orange sections and grapes. Makes 9 to 12 side-dish servings.