MIX cookie crumbs and butter; press onto bottom of 13x9-inch pan. Freeze until ready to use. Microwave peanut butter in small microwaveable bowl on HIGH 1 min.; stir. Swirl peanut butter into ice cream; spread over crust. Freeze 30 min.
MICROWAVE COOL WHIP and chocolate in medium microwaveable bowl on HIGH 1-1/2 to 2 min. or until chocolate is completely melted and mixture is well blended, stirring after each minute.
SPREAD COOL WHIP mixture over ice cream layer; top with nuts. Freeze 4 hours. Remove from freezer 10 min. before serving; let stand at room temperature to soften slightly before cutting to serve.