Welcome to the forum, glad you joined.
It's probably too late to help you since you're probably already at work but one solution would be to lock the hen and chick in one single nest instead of blocking all the other nests. That way the other nests would be open and available.
What are you doing for food and water? The hen is mostly living off of excess fat stored for that purpose, so she doesn't have to look for food and water while the hatch is ongoing. So she should be OK without eating or drinking. How old is the chick though? If it is older than three days it should be eating and drinking. It may survive until you get home but that's a long time to go without food and especially water.
The other hens can hold the egg for a while but I'd expect them to lay somewhere. They may all lay together or the eggs may be scattered. With living animals you don't get guarantees, you could get some weird eggs if they hold them long, anything from a deformed shell all the way to an egg within an egg, but the odds are all will lay a normal egg. One of the triggers for a hen to release a yolk to start tomorrow's egg is when she lays today's egg. You may see some reduced egg laying tomorrow. Or you may get a normal number of eggs. Only time will tell. As far as the other hens the biggest risk to me is that they learn to lay somewhere other than the nests.
It sounds like it was in a brooder, you had two chicks, and one died. For future reference, this is why we typically suggest you get a minimum of three chicks. You'd still have two and would not be in this situation.
From what I understand of your situation I would leave the chick in the brooder by itself until you can get the other chick. Put a mirror in if you can so it can see its reflection or maybe a stuffed animal it could snuggle with. Or maybe use a wooly hen, maybe just a mop head hanging in there so the chick could get under it. I'm guessing you woke up to a situation and just did something quick.
The hen may or may not accept the chick or chicks. The older the chicks the less likely that is, but some hens will adopt about any chick. Again you cannot tell what living animals will do. Not knowing what your set-up looks like it is hard to give specific suggestions so I have to be generic. If the hen does accept both chicks I suggest you set up an area that is safe for predators and leave them there. I have this aversion to bringing a broody hen with chicks into the house but your brooder may be your best temporary option.
With my set-up if the hen accepts the chicks and the chicks accept her I'd turn them loose with the rest of the flock and trust the broody to do what a broody does. But if your set-up is very tight you may be better off building a predator proof pen or a pen in a predator proof area and isolating them for awhile. If that pen can be where the others can see the hen and chicks even better, that may make integration easier later. But if you can't do that others totally isolate and deal with integration later.
I do not consider it cruel to take chicks from a broody hen. You will not permanently damage her self-esteem where you have to pipe in Dr. Phil to restore her. She will get over it in a couple of days. In your situation she may break from being broody, she may not.
Good luck with it, however you go.