Well, it is prison slang, but, I believe, in broad circulation. Maybe it is a bit dated. Wikipedia says it's in the OED: https://en.wikipedia.org/wiki/Nonce_(s

Well, it is prison slang, but, I believe, in broad circulation. Maybe it is a bit dated. Wikipedia says it's in the OED: https://en.wikipedia.org/wiki/Nonce_(slang) https://en.wikipedia.org/wiki/Nonce_(slang)