does paladin able to use holy shock whipe out nilahank temple non light immunity unit?

No offense but you're doing something wrong with that sorc of yours.
First and most obvious:

Griffon's Eye. If you want to run

Holy Shock on a sorc, you go with dual Dream, not Dream and griffon's.

Case and point: my trader is a dual Dream sorc, just for the hell of it (I blame the chronicle for having me make the first one... ^^) and even with nothing in her inventory (no light skillers, no torch, no anni, no sunder, ...) that entire room just blows up once she enters. On P1 at least.

Dream pally could do the same but worse because the pally synergies don't scale as well as light mastery does (pally is better for hoj/Dragon though).

A non-Dream, actual

Holy Shock pally could hit a higher aura lvl for more theoretical dmg per tick but he'd also forego the double-tick and force Infinity onto the merc (-> lower conv) so really no gain there.

Possible for all 3 though. Just not equally well.

With Infinity on the merc, it takes ~a couple pulses to clear the room.

For larger mobs (nihl) you have thunderstorm on top.

And the additional beauty of a Dream sorc is that as you pop in, you can just static everything a couple times at insane range (since you want that maxed for thunderstorm anyways) and reduce the number of pulses even further for whatever has a bit more life.

I mainly just use her to run cows when bored while sitting in a trade game. She does that just fine. And cows tend to be far more sturdy than

Nihlathak's adds.

If you add charms (which she won't..empty inv for trading and all) dmg goes up significantly as you're looking at a (renewed) sunder plus 11-12 more pts in

Lightning Mastery (depending on whether or not you keep room for a cube).

Mind you, Dream sorcs are definitely not a meta build by any means. But they can absolutely hold their own against pretty much anything and work better than you'd think for normal farming purposes (cows, keys, TZs, ...).