Nihilego @ Black Sludge  
Ability: Regenerator  
EVs: 248 HP / 156 Def / 104 SpD  
Calm Nature  
- Knock Off  
- Power Gem  
- Sludge Bomb  
- Stealth Rock / Toxic Spikes

Nihilego @ Power Herb  
Ability: Unburden  
EVs: 140 HP / 252 SpA / 116 Spe  
Modest Nature  
IVs: 0 Atk  
- Meteor Beam  
- Power Gem  
- Grass Knot  
- Sludge Bomb / Dazzling leam