Is this legit?

I think the mail address it was sent from wasn't nexon.net. If so, might be phishing.

Not that I'd give my phone and address to Nexon if it was legitimate

But the e-mail says to send it to webevents@nexon.net, so it's not like they'd get it anyway. That being said, it's written in the same format as mine, and I'm sure if you scrolled down there'd be the same legal warning, so it's pretty legit looking.

EDIT: Looked through my sent e-mails; I never actually gave them my ID either. Verifying my ID was just a matter of replying, I think.