DALnet's nick registration service allows users to register a nickname by providing a password, preventing other users from using it. NickServ registration is required for such things as registering channels and sending/receiving memos.
NickServ allows you to modify your nickname password using the PASSWD command. Prior to using this command, you are required identify with the current password. Upon a successful password change an email is sent to the email adress of the nick. No passwords will be included in that email. It is just a way to inform you that the password has been changed, and if you didnt issue that change, to take action and revoke it to prevent further damage.
Command: /nickserv set PASSWD (oldPassword) (newPassword)
Example: /nickserv set passwd 38hula alohA57