Originally Posted by 202dy
Gluing the missing piece back in place will not work for long. The broken part will shear off again. The nut will have to be replaced.
I had a break like that, put the missing piece back on with either Superglue or Gorilla glue (don't remember exactly), it's been fine ever since. That was a year ago. I do have a spare nut standing by in case it ever does break again, though. My advice would be to try the cheap fix; you can always take it to a pro later if the cheap fix doesn't take.