Chest freezers cool by having every wall of the thing get cold. If you divided it with a partition, both sides are going to get cold when it kicks on.
You would probably have to partition it and put a heat source on the side you wanted to be warmer.
All in all, it sounds pretty energy inefficient, though. With the cost of the temp controller and work to partition it, you might be better off just buying a mini fridge off craigslist and using that for the food.