Yes it's safe. After you thaw it, use as you would any cold leftover chicken.
You can thaw in fridge and eat cold. You can wrap in foil and reheat in oven and it really shouldn't come out too badly - put a little stock/broth in with it and it shouldn't dry out. Or you can nuke, saute. Use it just as you would roasted chicken you tucked into the fridge. I sometime buy them and pull the meat off and freeze and freeze the skin and carcass for stock.