How to get the nickname of a user


Is there a way for one user to obtain another user’s nickname from that user’s account information and not his own roster?

What I mean is this:

Suppose there are two users, user1 and user2. user1 tries to subscribe to user2 and thus user2 receives a presence packet asking for permission.

From the presence packet, user2 can obtain user1’s jid. What I want to know is if there is a way for user2 to also obtain user1’s nickname (the one that user1 gave himself during account creation) so that if user2 wants to add user1 to his roster, he can add the nickname that user1 gave himself instead of making one up for user1.

Thanks in advance for any help.