I'd say that "inek" firmly lies within what others would call "bookworm", having been called that. Maybe even implies a lot about schoolwork but not about much else. It implies that you don't have a personal life, because it is spent with schoolwork.
Nerd, on the other hand, conjures up a whole subculture that is quite different. The nerd not only is naturally good at schoolwork, but also has a personal life, but chooses to fill it with abnormal curiosa: Sci-fi, larping, reading, learning, etc.