>>49927030Sheer Force raises the base power of any affected move by 30%, and negates Life Orb recoil when you use an affected move. So, Earth Power ends up being ~4-5% stronger than Earthquake and doesn't make you take recoil damage, even though Nidoking's Attack is higher than his Special Attack.
The rest of Nidoking's physical moves are just lower BP than his special moves, and even if they weren't you'd still have to choose between full strength Earth Power and full strength coverage moves, so full special is the preferred set. You can run Hasty or Naive with Superpower on a special set though, a lot of the specially bulky Normals that switch into Nidoking take more from that than anything else even if you don't run Attack EVs.
