I presume you want each name on a different line, if so the following will allow you to add up to 5 names at a time and then will show you the file.
/nam write c:\names\ircnames $1 | write c:\names\ircnames $2 | write c:\names\ircnames $3 | write c:\names\ircnames $4 | write c:\names\ircnames $5 | /run c:\names\ircnames
or are you wanting to add a name plus some info about that person? then try the following
/nam write c:\names\ircnames $1 $2- | /run c:\names\ircnames