One of the stair nose came off and I’m trying to figure out the best way to put it back. There are tiny nails through the stair nose, and they all shifted. I think about removing them and applying some glue, but what is the best glue for the stairs? Any other ideas?
Remove the pins/nails, etc. and apply construction adhesive. Tape the molding securely in place overnight until it dries. If you have a brad nailer you could use that instead of tape.
I'm not sure what all that is "inside" the stair... but you'll want to clean that out and the adhesive should allow you to fill the void a little bit.