Baby chick with a broken foot

We would need more details and perhaps a picture. Sprains are common, and sometimes it is hard to tell whether it is the foot or the leg. Is the foot swollen? Are there any sores on the bottom of the foot (bumble foot infection) that might be hurting it? Sometimes a cotton ball in the ball of the foot and wrapping the foot in paper tape or vet wraps strips can help. Sometimes a shoe might work better. Other times it might help just to keep the chicken from running around, or keep it penned for a week or two. If it is a tiny chick, it might be okay to leave it alone unless the other chicks are hurting it. Here is a splinting manual with pictures of splinting:
https://theiwrc.org/wp-content/uploads/2011/05/Duerr_Splinting_Manual_2010.pdf