My girls will abandon the nest even if I lock them in, when I move them and the nest. Also, broody poos are SUPER gross!!!

I would NOT want that inside.
A lower pecking order girl definitely has a hard time defending a nest and makes it very difficult for her to hatch eggs.
If I wanted to adopt this hen some chicks... I would let her sit (wherever she chooses) until you could hatch eggs in the incubator and then give her the chicks. I don't like my girls to sit that long because they lose condition and get shaky. So I OFTEN adopt young feed store chicks to my broody hens!

They need to be broody for a good week IMO before getting chicks. Make sure the hormones are good and kicked in. So they know better what to do. I make sure the chicks are NOT more than 6 days old but younger is better. Most feed store chicks sold as day old will in fact be not less than 2-3 days old because they get them shipped from hatcheries just like everybody else. I call my feed stores to see what they have in or coming in within my parameters. Don't choose chicks with pasty butt! I have 2 stores and they get shipments every other week this time of year and they usually have different breeds than each other. I might wait a week or even two if they have breeds coming in that I'm interested in. That way they are sexed and WAY less chance of getting roosters, which I excel at hatching!

If you aren't ready to have boys be butchered it's an extra challenge to the hatching thing. It's difficult to find many homes.
I adopt the chicks a few a hours after dark. I move the broody, if I want her somewhere else. They *rarely* abandon a nest with chicks. I have locked them in to prevent abandonment or to prevent flock harassment, but I usually let them brood among the flock. She will be pecking wildly. So you have to shield the chicks while tucking them under her. Do this in the dark with a flash light. Tuck chicks quickly while lifting her and remove all eggs. (she will even brood just air even if you take away every egg every day). 1 time only a hen went to her original nest site before the chicks could follow. But not until she could see in the morning. That is why I am out their at dawn checking how it's going. And very very often for the first few days, especially day 1 though. Most of my hens will NOT leave a chick behind. They will sit in the middle of the floor if that's as far as a chick can go. I make sure food and water are near by during day time but removed to avoid rodents at night. She may not take the chicks off the nest for several days, but they will seek the food and water especially if they have already been eating and drinking before adoption. One reason I check often is to make sure the chicks know how to find their way back under mama. For me, not less than 3 chicks in case something happens to one. More than 5 seems a real hand full for the hen. mamma should take over. She should start clucking while they are under her so they can learn her voice. And before long tidbitting food. Once they can make it out, she won't occupy the nest with them all day. But it needs to be refreshed for the layers since the chicks poo in it all night.
You must be prepared to take them and raise them if it doesn't seem like it's working out.
Anyways, sorry so much detail.. I'm sure there's something I missed!
Can you tell... I love broody's!!