MICROWAVE chocolate and 1/2 cup COOL WHIP on HIGH 1 min. or until chocolate is melted, stirring after 1 min. Stir in zest. Spread onto bottom of crust; sprinkle with half the nuts.
BEAT pudding mixes and milk with whisk 2 min. Stir in 1-1/2 cups COOL WHIP. Pour into crust.
COVER with remaining COOL WHIP. Refrigerate 3 hours or until firm. Top with remaining nuts. Garnish with lime slices, if desired.