Prick plastic wrap covering apple chunks several times with a fork; microwave at medium power (50%) for 7 minutes or until apple is thawed. Let stand 2 minutes.
Meanwhile, melt butter in a large skillet over medium heat; add cookie crumbs and walnuts. Cook, stirring constantly, 2 minutes. Remove from heat, and stir in 1/4 cup brown sugar, 1/2 tsp. cinnamon and nutmeg.
Combine 2 Tbsp. brown sugar and remaining 1/2 tsp. cinnamon; sprinkle in a lightly greased 1-quart baking dish. Sprinkle half of apple over brown sugar mixture; top with half of cookie crumb mixture. Repeat layers with remaining apple and crumb mixture. Bake at 350 for 25 minutes or until golden. Serve warm with vanilla ice cream.