Exactly. In a pinch you can do something like that to get you through till a fix is possible. Super glue is a bad idea though. Most nuts are installed from the factory with wood glue, loads easier to deal with when repair or replacement is necessary. Never use super glue for anything on a guitar. Many amateurs do and it's a guitar tech's worst nightmare, really tough to remove without trashing a guitar or part of it.
Most of a guitar is usually put together with hide glue. Made from animal hides, hence the name, heated and clamped it holds really well and can be disassembled by reheating. Which is why an acoustic in a car trunk in Texas about mid July is a very bad idea...car trunk temperature is just about right to let the glue soften and let go...I've seen bridges that slid forward a half inch on a summer day...hide glue...nuts are usually done with regular elmers or wood glue, and just a drop of it against the vertical surface of the neck. String pressure does most of the holding. And it pops loose pretty easy, a bit of sanding maybe, and it's ready for replacement.
Nut slots should actually be ok for a string gauge change, chances are this one was not cut right to begin with or the smaller strings already cut deeper into the nut enough to get into a bind, and the larger strings are too tight.Probably sitting on the original slots, and burrs at the back holding them up...no telling without being able to see it.
My Epiphone was a great guitar, never had any trouble with it at all and I loved the zero fret. I was able to set the action so it played more like an electric, custom mixed gauge strings and I could do leads that amazed guitar players until they found out why. Big bottom end strings and light ones for high E,B and G. Worked and sounded great. But that zero fret gave it action most people couldn't believe. I attended parties with friends, 4 guitars. My $100 Epi, a 1957 Fender, very nice Alvarez, new Sigma electric acoustic. I never got to play mine, all the other guys always grabbed it...Around $4000 worth of guitars, my el cheapo was the one everybody wanted to play...I was very unhappy when it was stolen in Austin...I'd been playing it more than 10 years.
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