Do the.nails.move or r they really tightly in? If the move can u push them up a bit to release the clenches on the outside of the hoof then get heavy duty pliers and lift the clenches up so u can pull the nails out. X
R the nail head sheared off and in the shoe? If the nail heads r still on nail u will need to lift clench on outside of hoof and pull out from bottom of foot. If nail heads have def come off and no nail in bottom of foot should come out fairly easily from top of hoof if u can get hold of the nail. Where abouts r u? X
can you wiggle them out or are they quite tightly in? When my horse's shoe came off it left a couple of nails in I was able to wiggle most of them through. The last one I couldn't get out I left as the farrier was due within the next few days, I just put an overreach boot on so they nail didn't catch on his other foot or anything else. Has he gone lame on the foot?
If you can post a photo of the foot it would be helpful
If the clenches are visible on the hoof wall but still flush to the wall (that is, they are not sticking up and they are not at risk of causing injury) then leave them there for now.
If they are sticking up but you do not feel confident trying to remove them then either pop an overreach boot on or duct tape over the top of them (or both).
Your farrier will most likely call you in the morning and then he can come and advise.