nickname

hello everybody

I would like to know how to find the nickname of somebody to prepare openings

tks

I don't understand that request, but it surely doesn't sound like general chess discussion.

do you mean how do you prepare for a tournament?

YES when you prepare for a OTB game , It is useful to study games of your opponent even lichess games , but you must know his name used to play in lichess or chess.com

There is no connection between nickname and "real name". I am very sorry that I have to tell you so, but unfortunately this will not be possible.