Preheat oven to 450 degrees F. Beat cream cheese and sugar in large bowl with mixer until well blended. Add eggs and vanilla; beat well. Stir in 1 2/3 cups chocolate chips; pour into crust.
Bake 10 minutes. Without opening oven door, reduce oven temp. to 250 degrees F; continue baking 30 minutes or just until set. Remove from oven to wire rack. Cool completely. Cover; refrigerate until thoroughly chilled.
Place remaining 1/3 cup chips and whipping cream in small microwave-safe bowl. Microwave at HIGH 20-30 seconds or just until chips are melted and mixture is smooth when stirred. Cool slightly; spread over top of cheese pie. Refrigerate 15 min. or until topping is set.