This is one of the most discussed topics on this forum, so when you get a chance, try searching "rubber chicken skin", ""crispy chicken skin" or just "chicken". You'll get literally hundreds of suggestions for solving the problem, everything from using a blowtorch to scraping the fat off the skin to adding baking powder to your rub.
The long and short of it is, chicken skin is hard to make tender and damn near impossible to make crispy in a low heat smoker. Many folks, myself included, just raise the heat to 325˚ or higher to solve it. However, your MES won't get that high, so you can sear on a hot grill once the chicken gets to an internal temp of 150˚ or so, or put in a HOT (400˚+) oven for the same effect.
Keep at it! Chicken is one of my favorite meats to experiment with because it's cheap and almost always delicious.
Hope this helped a little. You'll get there!
EDIT** WHB and I were typing at the same time, he beat me to the punchline! :)