The only notable offensive buffs in the army are +1 to-hit (dark delusions), +1 to-wound in combat (Shardspeaker), and RR1’s to-hit, which can be done with warscroll daemon hero spells.
They’re all keyword agnostic, so Marauders, Depraved Bestigors, Gors, Bullgors, Chosen, and yes, Chaos Warriors, lose exploding 6’s but the difference simply isn’t great enough to make up for the existing warscroll cost imbalances.
Edit: Full rerolls to-hit are huge too, and are provided by the Lord of Pain which is key worded to Hedonite Mortals. StD get full rerolls to-hit and to-wound, though, with Warshrines and Sorcerers.