BEAT pudding mix, milk, 2 Tbsp. orange juice and nutmeg in large bowl with whisk 2 min. Gently stir in COOL WHIP.
SLICE cake horizontally into 4 layers. Sprinkle cake layers evenly with remaining orange juice. Cut into 1-inch cubes.
PLACE half the cake cubes onto bottom of 2-1/2-qt. straight-sided bowl. Spoon half the COOL WHIP mixture over cake cubes. Top with berries and nuts, reserving several for garnish, if desired. Layer remaining cake cubes and COOL WHIP mixture over nuts. Top with reserved berries and nuts. Refrigerate until ready to serve.