1 (8 oz.) pkg. nonfat cream cheese, room temperature
1 tsp. grated lime rind
1/3 c. fresh lime juice
sugar substitute to equal 1/4 c. sweetener
1 (8 oz.) container reduced-fat frozen nondairy whipped topping, thawed
1 prepared graham cracker crust (6 oz.)
8 thin lime slices (for garnish; optional)

Beat together cream cheese, lime rind, lime juice and sugar substitute with electric mixer on medium speed in large bowl until fluffy, 3 to 4 minutes. Fold in whipped topping. Spoon evenly into prepared graham cracker crust. Chill 4 hours or until the filling is firm. Garnish with the lime slices if desired.