WHISK together evaporated milk and egg yolks in medium saucepan. Heat over medium-low heat, stirring constantly, until mixture is very hot and thickens slightly; do not boil. Place morsels in food processor fitted with metal blade. With processor running, slowly pour milk mixture into chocolate. Process 10 to 20 seconds. Scrape down sides and continue processing until smooth.
POUR into crust. Refrigerate for 3 hours or until firm. Top with sweetened whipped cream before serving; sprinkle with nuts.