I have a nidoking (in my black version) with its hidden ability, sheer force. It has a high attack, and a somewhat low special attack (despite being bred with perfect special attack IVs), and I was wanting some good physical attacks for him that can take advantage of sheer force and his life orb. His current moves are: thunderbolt, earth power, sludge bomb, and flamethrower. I also have access to move tutors in black 2.
Honestly, I'd recommend keeping that moveset. All four moves have added effects, boosting their power due to Sheer Force. Then, the Life Orb boosts their power even further, with the ability negating the HP loss. If I were you, I would keep the move set as is.
If you really want to go for power, try replacing Thunderbolt with Thunder, Sludge Bomb with Sludge Wave (maybe, if you're okay with hitting allies in Double and Triple Battles), Flamethrower with Fire Blast, and leaving Earth Power as is.