STIR boiling water into dry gelatin mix in large bowl at least 2 min. until completely dissolved. Add enough ice to cold water to measure 1 cup. Add to gelatin; stir until slightly thickened. Remove any unmelted ice. Add 2 cups of the whipped topping; stir with wire whisk until well blended. Refrigerate 30 min. or until mixture is very thick and will mound.

SPOON into crust. Refrigerate 4 hours or until firm.

TOP with the remaining whipped topping just before serving. Store leftover pie in refrigerator.