Coat the insert of a 4-qt slow cooker with non-stick pray. Cut a piece of parchment to fit the bottom of the cooker and put it in place at the bottom
In a medium bowl, beat cake mix, eggs, butter and sour cream until smooth. Add the milk gradually then beat for 2 minutes on high speed. Stir in the 1/2 tsp cinnamon and the nutmeg. Set aside.
Using a food processor, sharp knife or potato masher, crush the pie filling to make smaller pieces. Stir in the cinnamon and brown sugar.
Spoon half the pie filling mixture in an even layer at the bottom of the slow cooker then top with half the cake batter. Spoon the remaining pie filling on top then the remaining batter, smoothing the top.
Cover and cook on hight for 2 1/2 hours. Remove the insert and lid and cool for 15 minutes. Invert onto a serving platter.
Cake mix box sizes vary—you will need the 2-layer size.