Nut glue?

Yeah, anything is fine. Nicer classicals don't even have the nuts glued in, because... why? If you have strings on it, the nut isn't going to get up and walk away! All you're doing is keeping it in place so it doesn't dart into the couch cushions when you're changing strings.

Superglue is okay if you just do a dab of medium or gel. That is the most common thing in factories. The thin stuff makes a mess if/when you have to take it out, and you're almost guaranteed to rip out wood in the process. Lately I've been using liquid hide glue, but if I didn't have it on hand I wouldn't go out and buy it just for that. Elmers would be a good choice after that. Something with water clean up is nice in case you get strings on and it squeezes out.

The only time I've had to be even remotely aggressive is with highly asymmetrical peghead designs because the strings want to whip it off to the side all the time.

C'mon you guys. SOMEBODY has to make some kind of adolescent remark about the thread title. You guys are slipping.

Just be careful not to use too much because it displaces easily and goes EVERYWHERE.

The last thing you want is nut glue all the way out to Uranus.

There you go, ninworks.

My most recent nutjob turned into a mess. I glued it with the aforementioned hide glue and filed down the nut slots. Then I determined that nut had to be moved a gnat hair toward the treble side. Using a small jeweler's flat blade as a chisel I gently tapped the nut loose but discovered it split it half. I super glued it together, reseated it and gently swiped the slots again, only to discover the d string was now laying flat on the first fret. Applying some previously learned Peegoonetics I dammed the slot, filled it with bone dust and CA, puffed it with accelerant vapor and recut the slot. Amazingly this abomination is holding and playing pretty darn well, but I have backup all ready when/if things go south. I would not trust this work to a gig, haha.

I doubled it for you.