Hey Mark, I thought maybe you were saying the nut operating the saw had gotten bigger after all the holiday eating!
I am not sure what size the nut is, but if you find a machine shop they may be able to fabricate one to your liking. I am guessing this is a lefthand thread, so a LH tap may be difficult to find. Must nuts are made to industry standards and I would think it would be unlikely to find anything in existance. I could be wrong though. Good luck!