I've had success with a broody that was only broody a few days, I've had failure. I think it is worth a try but observe.
Hopefully it is dark in your coop or wherever she is. After it is really dark put the chicks in the nest with her and remove any eggs she has. You don't have to put them under her, just next to her should work. If you do put them under her be careful not to crush a chick. They should crawl under her on their own. They should be OK overnight, she can't see them.
Go down early the next morning to see what is happening. You could see many different things. It is possible she could attack them to kill them or peck them to try to drive them away, not necessarily trying to kill them. It is possible she will ignore them. They may stay in the nest with her, crawling around under her and in the nest and she doesn't seem to notice or she may accept them. It's hard to tell these two apart. In either case I'd leave them, give them time to bond as long as she is not hurting them.
Do not expect her to immediately bring them off the nest. Even if she hatched them it may take her a couple of days for her to bring them off. They will tell her when they start to get hungry and thirsty. If you hear distressed peeping and she does not bring them off, you can take her and the chicks off the nest and see how they react. If she hops back on the nest you are brooding them yourself. If she calls them to her she is in charge.