Well they could tone down the Venom uses and still have Venom. He could sell it to quickly take over the criminal underworld. Criminals are afraid of Batman and desperate, so naturally they'd turn to a drug that would give them an edge against him, no matter what the side effects are. Batman gets worn out with Gotham's criminals on venom, allowing Bane to injure him. That way you have Venom and showcase Bane's natural physical and mental prowess. Maybe have Bane take Venom towards the end in desperation, which leads to his downfall.
Nolan Bane has a lot of potential to be great.