The nickname is not enough, because most people are bad with names.
I think the best solution would be a hanging namecard holder with the nickname and EP4EVER avatar. Like this, but not landscape orientation, portrait is better.
An additionally problem can be, people like to use the real name when talking with each other.
Imagine a situation, a forum member with name Kljt243. And then the conversation.
- Hey Kay-El-J-Tee two-four-three (with hungarian pronaunciation: Kéjeldzsítí-tú-fór-trí), how are you?