OP, are you using the standard, zzKRU, FOO, FOX, zFOST, zKylo FO team?
I Have to be honest NS teams should be very easy with that lineup although if they are using talzin lead spirit and have all the g12+ and great mods it can be a bit dodgy. Keep working on your gearing and your mods and FO will handle them fine.
Since plague can dispatch your fast FOO very quickly some FO players switch him out for FOSFTP specifically against NS, the extra AOE and a bit more HP make up for FOO's normal awesomeness.
I notice in your screen grab Daka is still alive so maybe you also need to work on your kill order. After killing the weakest nightsister 2 times make sure you focus on getting Daka killed next. Use FOX and FOO's TM reduction to keep zombies taunt at bay if your FOX isn't powerful enough to 1 shoot her twice in a row. If talia is in the team you may want to use Halt on her as otherwise she'll use her cleanse which is very annoying. In other lineups you'll probably have most luck using halt on Talzin to delay the inevitable spreading of the plague or spirit to avoid too many stuns.
Good luck!