Chickens heal remarkably well. You can use most any antiseptic or antibiotic except those with "caine" drugs in them such as benzocaine or solarcaine. You can use bag balm if you have that, too.
Mostly, she needs a warm, safe place to live til she heals, away from the flock so the others dont peck the wound, which they will. A spare bathroom tub is ideal.
As long as she is eating and drinking, whe should be fine. It may take her a day or so to get over the shock of the situation before she eats and drinks well. You can encourage drinking, the most important, by dropping a drop of water along the side of her beak til she pulls it into her mouth, then give another, etc. Soft foods for a few days like scrambled eggs and cooked cereal may help, too.
Good luck!