XY OU Trying to make a Sunny Day Doubles team. 1st team I've built.

[RonNid]

I know straight away some of the glaringly obvious problems with the team, but I'm just sticking them up to see what other issues it has.

The idea is that I start with Chestnaught, along with either Charizard Y or rotom Heat. Then I let Rotom/Charizard take out any flying types, while Chestnaught keeps working on a rotation of his moves. I've tested it a few times and have lost each time. But not very badly, always was one of those "shoot, so close!" type battles. The most glaringly obvious issue is the teams general weakness to flying/electric types, so who should leave to be replaced by something to deal with those types?

Chester (Chesnaught) (M) @ Leftovers
Ability: Bulletproof
Shiny: Yes
EVs: 4 HP / 252 Def / 252 SpD
Impish Nature
- Synthesis
- Spiky Shield
- Spikes
- Leech Seed/Roar

Nidoking @ Life Orb
Ability: Sheer Force
Shiny: Yes
EVs: 4 Atk / 252 SpA / 252 Spe
Mild Nature
- Earth Power
- Sludge Wave
- Megahorn
- Thunder

Rotom-Heat @ Heat Rock
Ability: Levitate
EVs: 128 Def / 252 SpA / 128 SpD
Modest Nature
- Sunny Day
- Thunderbolt
- Volt Switch
- Thunder Wave

Dragonite @ Dragon Fang
Ability: Multiscale
- Dragon Rush
- Earthquake
- Extreme Speed
- Dragon Dance

Charizard-Mega-Y @ Charizardite Y
Ability: Drought
EVs: 4 HP / 252 SpA / 252 Spe
Rash Nature
- Solar Beam
- Fire Blast
- Focus Blast
- Roost

Talonflame @ Sitrus Berry
Ability: Flame Body
EVs: 4 HP / 252 Atk / 252 Spe
Lonely Nature
- Brave Bird
- Flare Blitz
- Roost
- Tailwind

 

[MosImba]

I'm not very experienced with Sunny Day teams, but I will give you my best input. I would replace Chesnaught with Chlorophyll Venusuar with a defensive nature to give yourself that resistance to Water and Rock, or you can go with Ferrothorn to set up rocks, your choice. There are better Dragons than Dragonite to use in Doubles, consider Hydreigon or even Goodra. I don't know what to mae of the Nidoking, unfortunately, so I guess keep working with it. That is all I have to say, I'm sure somebody more experienced than me can tell you EXACTLY what to fix.