Here's a Nidoqueen I made that I absolutely love. I have tested it.
This Nidoqueen is an ideal situational counter to sandstorm users. It can easily counter Tyranitars, Excadrills, Gliscors, Celebis, and if you're lucky, and the Hydro Pump misses, it can hurt Rotom-W. Unless it switches, it also makes a good counter to Landorus.
Nidoqueen @ Air Balloon
EVs: 106 HP, 152 DEF, 252 Spc. ATTK/152 ATTK, 152 Def, 200 ATTK
Nature: Modest/Rash
Ability: Sheer Force
Focus Blast/Superpower
Earth Power
Ice Beam
Hone Claws/Sludge Bomb
This Nidoqueen, with excellent type coverage, makes an idealistic counter to the infamous sandstorm build of Tyranitar, Gliscor, Excadrill, and Celebi/Rotom-W. Focus Blast, with Sheer Force and impressive base 120 power, can easily OHKO Tyranitar, especially with Stealth Rock. It also makes an excellent substitute for Earth Power in case the opponent's Excadrill has Air Balloon. Ice Beam obliterates Gliscor and badly hurts Celebi, and Focus Blast puts a fair dent in Rotom-W. The strategy is simple. Come in on an anticipated Earthquake. When the Excadrill uses Rock Slide to brake the Balloon, KO it with Focus Blast or Earth Power, depending on the Excadrill's item. Against Tyranitar, just KO it with Focus Blast, because all forms of Tyranitar except Scarfed and the very rare Dragon Dance variants are outsped. It is very imprortant that Focus Blast doesn't miss, so if you get the chance, use Hone Claws.
Other Options:
If you want to use Superpower, give Nidoking 152 ATTK over HP. With Stealth Rock, this allows Superpower to always OHKO Tyranitar, but the special attack loss from moving EVs hurts her chances at OHKOing certain threats. This also however lowers Nidoqueen's Special Defense, and without HP EVs, Hydro Pump will always OHKO. The only advantage is the accuracy of Superpower, so the fully special version is advised, not to mention that all three of its attacks gain Sheer Force.