SM OU Some help for this Mega Diancie + Dual Dance Mew team please?

[SohamSpur]

Skarmory @ Rocky Helmet
Ability: Sturdy
EVs: 252 HP / 232 Def / 24 Spe
Impish Nature
- Spikes
- Whirlwind
- Brave Bird
- Roost

Mew @ Mewnium Z
Ability: Synchronize
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Nasty Plot
- Rock Polish
- Psychic
- Fire Blast

Diancie-Mega @ Diancite
Ability: Clear Body
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Moonblast
- Rock Polish
- Hidden Power [Fire]
- Earth Power

Chansey @ Eviolite
Ability: Natural Cure
EVs: 248 HP / 252 Def / 8 SpD
Bold Nature
IVs: 0 Atk
- Soft-Boiled
- Seismic Toss
- Toxic
- Stealth Rock

Nidoking @ Life Orb
Ability: Sheer Force
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Sludge Wave
- Earth Power
- Ice Beam
- Flamethrower

Kartana @ Choice Scarf
Ability: Beast Boost
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Leaf Blade
- Sacred Sword
- Defog
- Knock Off

 

[Gross Sweep]

Welcome to Smogon! I'm locking your RMT for the time being as the forum rules require that you provide in-depth descriptions for each Pokemon to explain their roles. Please read the rules carefully and take a look at Team Showcase to see the level of detail we require. PM me with updated descriptions and I'll be happy to unlock this.