Preheat oven to 350° F.
Microwave morsels and butter in medium, microwave-safe bowl on MEDIUM-HIGH (70%) power for 1 minute; stir.
Microwave at additional 10- to 20-second intervals, stirring until smooth.
Stir in crumbs and nuts.
Reserve 2 cups crumb mixture; press remaining mixture into ungreased 15 x 10-inch jelly-roll pan.
Bake for 12 minutes.
Beat cream cheese and sugar in large mixer bowl until creamy.
Add eggs one at a time, beating well after each addition.
Beat in flour and lemon juice.
Pour over crust; sprinkle with reserved crumb mixture.
Bake for 20 to 25 minutes or until set.
Cool in pan on wire rack.
Cut into bars or diamonds; refrigerate.