Not a bad suggestion but I think this should be part of what has been asked many times in the past, a way to define servers to join automatically, with nicknames set per server etc..
Also, while I'm on the subject, I'm always bothered by the way mIRC sets my primary vs. alternate nick.. it seems that if I use my alternate nick, even if mIRC uses it automatically, it then becomes my primary until I bother to change it.. and even figuring out how to change it isn't that easy. (I don't remember what the issue was, I guess that you can't change that mIRC setting while you're connected).
I wish mIRC would just *keep* my defined primary nick as my primary and my alternate as my alternate, unless and until I define it differently.
mIRC doesn't change your main nickname unless you use /nick to change it yourself, I believe. However there is an option to keep it from doing that, check 'preserve nicknames' in alt + o > Connect > options