NickServ allows you to change the password you used
when you first registered your nickname using the PASSWD command. Before
you use it, you need to use the IDENTIFY
command, to prove you are the real nickname owner. After you do, you use this
command to change your password:
/NickServ SET PASSWD NewPasswordHere
Please note that neither the old password or the nickname appear anywhere on
this command. NickServ will change the password for the nickname you are
currently using.
The same cautions apply to this password as when you first registered. That is:
the password is CaSe SeNsiTiVe, and should be kept secret.