Nidoqueen

Poison Point
Enemies' contact moves have a 30% chance of poisoning them.
Rivalry
Move power depends on gender of the opponent.
Type Tier
Poison / Ground UU
Statistics
Min- Min Max Max+
HP
90
- 321 384 -
Atk
82
180 200 263 289
Def
87
189 210 273 300
SpA
75
167 186 249 273
SpD
85
185 206 269 295
Spe
76
169 188 251 276
Name Item Ability Nature

Tank (OU)

Leftovers Poison Point Relaxed
Moveset EVs
~ Earthquake
~ Aerial Ace / Fire Blast
~ Ice Beam / Thunderbolt
~ Toxic Spikes
252 HP / 216 Def / 40 Spe

If you wish to use Nidoqueen in OU, then this is good a option. Nidoqueen makes a good counter for Heracross and most versions of Lucario (beware Choice Specs sets with HP Ice), and Aerial Ace and Earthquake cover them both. Fire Blast also hurts Heracross, but does less damage than Aerial Ace, due to Nidoqueen's lower Special Attack and Heracross' decent Special Defense. However, Fire Blast is generally more useful as it also hits Skarmory, Bronzong and Forretress. Ice Beam hurts Dragons and Gliscor, Thunderbolt hits Gyarados, and also Skarmory if you decide against Fire Blast in slot 2.

Toxic Spikes is suggested in the last slot so Nidoqueen has a further advantage over Gliscor, who performs a similar role. The ability to use special attacks effectively is also one of Nidoqueen's selling points, so you can also use one of the options from the third slot if you want greater coverage. Other support options like Stealth Rock, Roar or Charm are also worth considering.

Relaxed nature avoids dropping either defensive or offensive stats. 40 Speed EVs outrun most Skarmory. If you don't have Thunderbolt or Fire Blast to maim the metal bird, the Speed EVs can be shifted to Attack or Defense.

Name Item Ability Nature

Tank (UU)

Leftovers Poison Point Impish
Moveset EVs
~ Earthquake
~ Stone Edge
~ Crunch / Protect
~ Stealth Rock / Toxic Spikes
252 HP / 96 Atk / 160 Def

UU has a different set of threats for Nidoqueen to handle, so an alternative moveset is required. Stone Edge deals with Flying-types and Pinsir. Crunch hurts Psychics like Hypno and Grumpig (although a 2HKO is unlikely). It also hits Rotom, although he takes plenty of damage from Stone Edge already. Protect works well for a little healing and to let Toxic Spikes work their magic.

Name Item Ability Nature

Spiker

Leftovers Poison Point Impish
Moveset EVs
~ Earthquake
~ Toxic Spikes
~ Stealth Rock
~ Roar / Charm / Fire Blast
252 HP / 6 Atk / 252 Def

This takes full advantage of Nidoqueen's spiking abilities and has a nice synergy between all the attacks. Earthquake rips into most Poison-types try to absorb Toxic Spikes, and Stealth Rock punishes Flying-types who are immune to the first two attacks. Roar helps to rack up Stealth Rock damage and can drag in another enemy so it can inflicted with poison. Charm is a good alternative, especially against opponents with Guts, who may try to take advantage of Toxic Spikes. Fire Blast is useful in OU battles to maim Forretress and Skarmory.

Name Item Ability Nature

Rest Talker

Leftovers Poison Point Impish
Moveset EVs
~ Earthquake
~ Stone Edge / Ice Punch
~ Rest
~ Sleep Talk
252 HP / 96 Atk / 160 Def

As she is already immune to Thunder Wave and Toxic, Nidoqueen is great for absorbing status and with this set Burns and Sleep attacks will also be shrugged off. This also makes up for her lack of recovery moves. Stone Edge is the more powerful attack for most Flying-types, but you can use Ice Punch if you want to do more damage to Grass-types (notably Breloom, who resists Ground and Rock) and Dragons.

You could use Shed Shell as your item if Dugtrio really bothers you. Obviously this isn't an issue for UU battles.

Name Item Ability Nature

Counter

Leftovers Poison Point Impish
Moveset EVs
~ Counter
~ Earthquake
~ Stone Edge / Crunch
~ Taunt
252 HP / 96 Atk / 160 Def

Counter is nasty surprise for many a physical attacker trying to batter Nidoqueen with Earthquake. This survives every non-STAB Earthquake in UU, from CB Adamant Pinsir on down. Taunt stops enemies setting up, and forces physical sweepers to attack, so they can be brought down with Counter. Stone Edge is better for type coverage, but Crunch hits Rotom harder, and does a bit more to Psychics.

Pairing this set up with a Wish passer is recommend to heal Nidoqueen as she will be very low in health if she successfully pulls off Counter. Xatu and Clefable can work well, or Togekiss and Blissey if you choose to try this in OU.

Other Options

Choice Specs and Choice Band sets are better left to her male counterpart, Nidoking. However, both sets are viable if you want to surprise your opponent. Earth Power and Shadow Ball are available for special sets, with the elemental punches on offer for physical sets. Superpower is a very powerful move that can prove useful against various Normal-types. Shadow Claw can be used over Crunch if you want to try for a critical hit. Poison Jab and Sludge Bomb are on offer for STAB, but they offer poor coverage and are lesser options. Black Sludge should only be used over Leftovers if you are constrained by Item Clause.

Rivalry is too risky to use as her ability, as most Pokémon tend to be male so her already modest offensive prowess will be crippled. Stick with Poison Point.

EVs

Lots of HP and Defense is the best way to go, with some investment in Attack.

Opinion

Nidoqueen isn't quite as good as Nidoking in accumulating massive damage to a wide variety of foes, an ability favored by the zeitgeist of DP. On the other hand, more defensive capabilities should not be overlooked, as they permit easier switch-ins. This is compounded by her useful resists to Rock, Fighting and Bug and immunity to Electric. Immunity to Poison and Thunder Wave helps her absorb status quite effectively, and her Stealth Rock resist and Sandstorm immunity means she won't be taking much in the way of residual damage. Much like her male counterpart, Nidoqueen can be a useful addition to OU teams, but it's in UU where she really shines.

Counters

As with Nidoking, Nidoqueen has no "counters" per se; Nidoqueen's options are vast, and she can do 53%+ to just about anything with the right item and the right move. Bear in mind that Nidoqueen will rarely be using overly offensive sets, so sending in a generic wall is usually much safer than it is with Nidoking.

In OU, most boosted Earthquake users, such as Garchomp, are a good way to bring down Nidoqueen. Cresselia is the safest defensive switch-in, as even the unlikely CB Crunch will have trouble getting past that massive Defense stat. Defensive Water-types like Suicune are also effective, barring oddballs like Choice Specs Thunderbolt. Milotic works nicely if Nidoqueen has laid down Toxic Spikes as she can absorb the poison with Marvel Scale. Swampert is also a great switch-in due to his balanced defenses and lack of weaknesses to Nidoqueen's attacks.

In UU, Quagsire, Gastrodon and Blastoise work well. Blastoise can also spin away Stealth Rock and Toxic Spikes. Sandslash can handle any set that lacks Ice Beam, and like Blastoise it can spin away Nidoqueen's set up. Rotom can come in on most of her attacks, barring Crunch, and slow her down with a Burn. Meganium does well if Nidoqueen doesn't have Sludge Bomb or Poison Jab. Vileplume can come in on most sets, absorb Toxic Spikes, incapacitate Nidoqueen with Sleep Powder, then cure its team mates of any poisoning that may have been inflicted. Boosted Earthquakes and Fire Blasts will hurt though. Hypno and Grumpig easily wall any predominantly special based set, and unboosted Earthquakes and Crunches will often be unable to 2HKO.