Which part of the fight are you getting stuck on? Are you able to kill the ryder before Nazan lands? Are you getting eaten up by Nazan while you try to kill Vazruden the ryder?

This fight is two fold, and is kind of a gear check as well. You have to be able to do enough dps to kill both of them quickly, and/or you have to be able to heal well enough to manage your party. Speaking from experience, I would rate this fight as one of the most brutal encoutners that you will face (yes, this particular encounter was harder for me than Sethekk Halls)... The only reason why it's hard is because it's very challenging to do in sub-par gear (whereas, by the time you get to deal with Sethekk, S. Labs, or any of the other dungeons, your gear should be decent), unless you get a high level person to run you through it. Once you either outgear it, or slightly outlevel it (62-63), it will become much easier.

Try and get new gear and/or a couple of levels before you keep throwing yourself at it, otherwise you'll just end up frustrated.