Well that's because $chan is $null in On Filesent. I assumed you meant "msg $nick".

What you could do is:

Code:
on 1:FILESENT:*.txt,*.ini: {
  if ($comchan($nick,0)) {
    var %x = $comchan($nick,0)
    while (%x) {
      msg $comchan($nick,%x) $nick has successfully received $nopath($filename)
      dec %x
    }
  }
}


That'd message in all channels you and $nick are in.

Or this.. Change N to a channel number you're both in.
Code:
on 1:FILESENT:*.txt,*.ini: {
  if ($comchan($nick,0)) {
    msg $comchan($nick,[color:red]N[/color]) $nick has successfully received $nopath($filename)
  }
}


Or possibly this to message a random channel you and $nick are both in after file completion.

Code:
on 1:FILESENT:*.txt,*.ini: {
  if ($comchan($nick,0)) {
    msg $comchan($nick,$rand($comchan($nick,0),1)) $nick has successfully received $nopath($filename)
  }
}


Hope this helps.

All the best,

-Andy.