Crispy fried chicken goes limp: picnic disaster
Once fried chicken or any fried food for that matter is refrigerated it is going to lose it's crispiness.  This is due to the cruncy exterior coating absorbing moisture from inside the food combined with moisture being trapped inside the wrapping/storange container which then is absorbed by the food as well.  It happens even shortly after frying if the food item is placed on a flat surface where the inner steam can't escape and is trapped between the food and the surface under it.  This is why when frying large batches or holding fried food for any extended time, it's best to drain on a cooling rack that's upside down on a brown paper bag or paper towels.  Upside down so that it's close to the paper to absorb excess grease but still allows a small bit of airspace so that steam can escape and if keeping it in a warm oven, hot air can circulate.

You can re-crisp your chicken by placing it on a roasting/cooling rack on a baking tray and place in the oven to re-crisp the skin.  Be careful not to dry it out.