I have used a large wired dog crate.....and inside the coop I have used a smaller dog crate with the bottom removed for a broody who refused to be moved.....make sure theres plenty of water and feed and treats..sometimes I have to hand feed my broody because she would refuse to get up....I used the crates so the other chickens wouldn't bug her and also so they couldnt lay more eggs for her to lay on...also so the big girls wont hurt the babies once they hatch....
2 of them are in the main coop - these 2 have taken over the least desireable nesting spaces, so no one bothers them. I've never seen them get pulled off their nest or found extra eggs in with the girls. I may move them later, but they're okay right now.
My other 2 broodies are in my old brooder box - they've hatched their eggs and are co-parenting their babies. It's a 4x4x2 wood crate with a wire top. I put these girls in the brooder when they were still sitting on their eggs because they had taken over the most popular nesting boxes and were getting dragged off their nests all the time by the other hens.
You could use a rabbit hutch, dog crate, etc for your broody - or leave her where she is, if the others are leaving her alone.