Turn Ideas/Suggestios:
Charge Savage Orks into Archers. The Steam Tank will likely be held up by the Night Goblins and unable to come to their aid. You'll probably overrun into the larger Outrider unit. He'll loose a lot of chaff and firepower. After you pummel them in his turn you can reform to face him for you next turn.
Setup Black Orcs to kill knights when they come back on. Probably overkill but they need to die.
Launch the fanatics from charging NG1 as a screen between their flank and the Greatswords. Make them pay for that semi-inevitable flank charge.
Remaining warmachines focus on Knights and Inner Circle in that order, assuming they can see them. If not, start milling those Greatswords.
NG2 tries to Swift Reform and begins moving toward the right. They can setup for a counter charge or support for the Savage after they do their job. Maybe fling some desperate arrows into some archers.
Magic should try to buff/eliminate the Witch Hunter. Without the MR(2) you can, hopefully, snipe a wizard or two. Plus, that guy can apparently shoot and thus needs to die and quickly.
If all goes as planned, you'll be prepared to defend your backfield, severely lowered his mobility, and reset your battle line in a south-easterly direction by the time his turn ends.
Hell, now may be the right time to call a Whaaaaghh! if orcs have such a rule (more familiar with 40k orcs, only played against fantasy twice but their generals were terrible.)