Some chicks are just not meant to make it. If you deal with living animals, you sometimes have to deal with dead or dying animals. And if it is malformed, it may be kinder to end it quickly. So just be prepared.
What you are doing sounds about right. Try keeping it warm, around 90 to 95 degrees, and see that it is eating and drinking. If it is very young, like less than three days old, it really does not need to eat and drink, but I'd feed and water it anyway. It maybe that it is so young that it just needs to rest and recover from a rough hatch, or maybe Mama left the nest before it was totally ready. It could maybe have even hatched after she left.
I suggest trying to get it some high energy food. Sugar water or maybe that hummingbird syrup would work. Be careful not to force liquid down its throat and drown it, but mybe use a medicine dropper to put a drop or two in the tip of its beak. The idea is to get its energy up to where it feels like eating and drinking on its own.
Good luck! This could be a rough situation or you may feel real good when it is over. I really hope it is the feel good.