Nidoking can be an absolute monster if you use it right. all though it lacks speed it makes up for in its diverse movepool. nidoking is viable in a range of tiers such as monotype, OU and UU, all though its sitting in UU at the moment it can be used as a OU meta check, nidoking is better with a special set, all though its atk is higher its special movepool is outstanding with moves such as t-bolt, ice beam, sludge wave, earth power , fire blast t thrower, shadow ball, focus blast and surf. nidoking can even be a hazard setter thanks to stealth rocks and t spikes. nidokings ability sheer force just complements its special movepool combined with life orb it can have high coverage and decent damage output. however its speed is not so great, you can use scarf if you want so you can outspeed lando, gren , non sg magearna non dd zygarde and many other things that threaten it. however with using scarf your damage output wont be as good without life orb but what does that do to 4x weaknesses plus STAB.
for OU I would go with this set:
Nidoking @ Life Orb
Ability: Sheer Force
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
- Earth Power
- Sludge Wave
- Ice Beam
- Substitute
source- smogon.com (more info on the set here http://www.smogon.com/dex/sm/pokemon/nidoking/ plus uu sets and monotype sets)
hope this helps and you didn't mean in game! XD
