I have done this for a few items in my pack I do not see why it would not work for Snickers.

If you can stand to pack a couple extra oz. at the time of need why not just chill your
Chocolate ??

Pack along an extra cotton sweat sock and a piece of cord.
When you want something cold and it happens to be hot weather just
soak the sock in water and put your selected "items" in the sock and
then hang your "cooler" where any breeze can reach it or tie it to the outside of your pack. As the water evaporates it will chill whatever you have
in the sock. This works great for my "gin n tonic", Beer, Soda etc. I do not see why it would not work for Chocolate.
I will say however that I have never checked the "chill factor" with a thermometer, I just know it works for my drinks.