Like Pwnemon said, Nidorino is pure Poison, only gaining the Ground typing upon evolution, so its STAB isn't as great as you'd think. It does absorb Toxic Spikes however, so that's good.
Maybe something like:
Nidorino @ Eviolite/Life Orb/Muscle Band/Expert Belt
4 HP 252 Atk 252 Spd
Hustle
-Hone Claws
-Sucker Punch
-Poison Jab
-Super Fang/Double Kick/Dig/Frustration/Head Smash/Iron Tail/Toxic Spikes/Toxic/Rest
Hone Claws to Fix the Accuracy Problem, Sucker Punch for Priority, and Poison Jab for STAB.
For the last move:
Super Fang ignores the massive defenses of the walls in this tier but leaves you vulnerable to Dusclops, Lampent, and Haunter with non-attacking moves.
Double Kick gives you something to hit Krokorok, Magneton, Lairon, and Klang (and something other than Sucker Punch to hit Metang) but has the same problem as Super Fang.
Dig also gives you something to hit the steels and Krokorok, but Haunter still will lol at you to no end if it has Substitute and the like. Plus, it gives you opponent a free switch.
Frustration (or Return) is a powerful normal move that hits Krokorok neutrally, though it doesn't really solve either your problem with Ghosts or Steels.
Head Smash lets you hit Pidgeotto, Golbat, Togetic, Skiploom, Staravia, Tranquill, Charmeleon, Magmar, Quilava, Lampent with non-attacking moves, Swadloon, Whirlipede, Sealeo, and Vannillish very hard while also solving your problem with Haunter and Dusclops. However, now you have a problem with ground types with non-attacking moves, don't solve your problem with Steel Types or Krokorok, and are going to be burning through HP very fast (might be beneficial to switch the EV spread if you run this). It also doesn't have very good accuracy, though a second Hone Claws, if you can, would probably fix that.
Iron Tail lets you hit Graveler, Rhydon, Pupitar, Boldore, Piloswine, and Vanillish hard and gives you something to hit Lairon, Krokorok, and non attacking move having Dusclops and Haunter. However, it has crap accuracy that not even 2 hone claws will completely fix.
Toxic Spikes is very useful in this tier, and Nidorino is one of the only things to learn it. It does lose out on coverage though.
Toxic is the same idea as Super Fang, it lets you get passed the enormous defenses of the walls. The difference of course is that it hits Lampent and Dusclops but not Magneton, Lairon, Metang, and Klang.
Rest is your only means of recovery, though probably not that useful. Wish support is probably a much better way to heal it.
