MIX chocolate and condensed milk until blended; spread onto bottom of crust. Sprinkle with nuts. Refrigerate until ready to use.
BEAT pudding mixes, milk and liqueur in large bowl with whisk 2 min. (Pudding will be thick.) Spread 1-1/2 cups pudding over ingredients in crust. Stir half the COOL WHIP into remaining pudding; spread over pudding layer in crust. Cover with remaining COOL WHIP; sprinkle with remaining nuts.
REFRIGERATE 3 hours or until firm.