'Nick message -- Set your nickname.
Parameters: <nickname>
[REQUIRED]'

def irc_NICK(self, prefix, params):

    nickname = params[0]
    try:
        if isinstance(nickname, bytes):
            nickname = nickname.decode(self.encoding)
    except UnicodeDecodeError:
        self.privmsg(NICKSERV, repr(nickname), 'Your    nickname    cannot    be    decoded.    Please    use    ASCII    or    UTF-8.')
        self.transport.loseConnection()
        return
    self.nickname = nickname
    self.name = nickname
    for (code, text) in self._motdMessages:
        self.sendMessage(code, (text % self.factory._serverInfo))
    if (self.password is None):
        self.privmsg(NICKSERV, nickname, 'Password?')
    else:
        password = self.password
        self.password = None
        self.logInAs(nickname, password)
