- GlompiJanuary 2019
As far as I know, mainly a difference in formality. "Nobody" is less formal than "no one" is, so you'll find it used less often in formal contexts.
Yes, "nobody" is usually less formal and, I'm sure, more often used in spoken language than "no one". However, there is a specific instance where you use "no one" instead of "nobody" - even when speaking informally. That is, if you are referring back to that absence of a person/people indicated by "no one".