1Heat oven to 400°F. Spray 9-inch square pan with cooking spray. In smal bowl, mix 2/3 cup Bisquick mix, brown sugar, cinnamon and nutmeg. Cut in butter, using pastry blender (or pulling 2 knives through ingredients in opposite directions), until crumbly; set aside.
2In medium bowl, stir together 2 cups Bisquick mix, 2/3 cup milk, the granulated sugar and egg; beat vigorously 30 seconds with spoon. Spread half of batter in pan. Arrange apple slices on batter; sprinkle with half of streusel topping. Spread with remaining batter; sprinkle with remaining topping. Sprinkle with nuts.
3Bake about 25 minutes or until toothpick inserted in center comes out clean. Cool in pan on cooling rack 20 minutes. In small bowl, stir glaze ingredients until smooth enough to drizzle. Drizzle glaze over warm coffee cake.