I think I've used everything from wood glue, to super glue to hide glue. So basically anything.
It's the only part of a CBG for which it's appropriate: Superglue (CA glue)! Sets quickly, and you can easily snap the nut back off by levering it with a knife. Wood glue would probably tear the wood if you needed to remove it.
I just use a drop or two of titebond
That design your talking about is never going to happen on one of my canjos. Made out of an old tin can and a stick.