vintage "Global" guitar repair

Hello all,
I have a question about a guitar I want to have repaired, it's an old global acoustic guitar, and from my bit of information that I've gathered, possibly from the 60's-70's. My issue is that when I tried to change the strings the top nut broke and flew across the room, it looks a little odd to me and I'm worried i might not be able to get it fixed. I figured I'd come here to ask around before I have to go anywhere and have it checked out. Will post pictures, thanks in advance.