It defiantly looks broken. I would put a small splint on the leg. Get a lollypop stick, gauze and some good tape
firmly grab your chick and have someone hold it down.. Grab the leg firmly but gently not to further hurt your chick,put leg in a natural position, then place the stick on the leg, firmly wrap the gauze around the leg and the stick, not to tight though. then tape it all in place. You could let it heal on it's own but that can turn out with its leg being crooked. Give it some sugary water, vegetables and boiled eggs or scrambled eggs are both good for chicks/chickens and they love it!
Good luck I hope it gets better!