Hi there! I think that your best choice in 1k points would be Coteaz but if you want to stick with the OM
Inq here's a list (not the most competitive but fun no less
IMO) :
Hq:
OM
Inq w/ Terminator armor + Psycannon +
NDH + Phycker Master
lvl 1 (Rolls on Divination for Primaris + random power) 110
Elites:
10x Purifier Squad w/ 6x
NFH (Justicar included) + 1x
NDH + 4x Psycannons in a Razorback w/ Psybolt ammo 345
Troops:
5x Terminator Squad w/ 1x Psycannon + 1x
NFH (Justicar Thawn) + 2x
NFS (1 of them on Psycannon) +2x
NDH 300
5x
GKSS w/ 1x Psycannon 110
Heavy Support:
Dreadnought w/ 2x
TL autocannons + Psybolt ammo 135
As for Tactics you Combat Squad your Purifiers . One group has 4x
NFH + 1x
NDH and run into offensive in the Psyback .The other has your Justicar + 4x Psycannons and you let
Inq join them . 5x Psycannons with rerolls to hit + Halberd or Hammer for the challenges if need be . Problem is that this unit has to footslog in middlefields and its only protection is the
Inq's
TDA of 5++ .. Dread adds supporting fire ..
GKSS can
DS if need be and the Ternies try to hunt down opponent's troops/elites . Thawn may be expensive but know he generates 2 WP and he can be another troop by himself after he had tanked some
AP 1/2 for the squad .. Talking about WP this list can produce 1d6 + 8 WP every turn.. As for
AA if someone brings something you can always try to snap shot with Psycannons or the Dread ..
Hope this helps!!