Hello Anonymous, I'm afraid that's not correct. "Nice seeing you" is fine for saying good-bye, but not "nice meeting you." Both "nice to meet you" and "Nice meeting you" are reserved for the first time you actually meet.
Hi, actually I'm nonnative but I learned this in the book "Spectrum 1A, by Diana Warshawsky with Donald R.H. Byrd,page 26" and also Top Notch 1A, page 2 by Joan Saslo & Allen Ascher. these books for me as nonnative are source.
Well, if these books re telling you that "Nice meeting you is one of the ways to say goodbye whether it is first meeting or not," then they are simply wrong.