I also used a slightly different spread for my Magnezone and gave him Modest nature.
Magenato (Magnezone) @ Air Balloon
Trait: Magnet Pull
EVs: 56 HP / 255 SAtk / 196 Spd
Modest Nature (+SAtk, -Atk)
- Hidden Power [Fire]
- Magnet Rise
You could definitely do with another Physical Sweeper on the team. Dunno what though.
I saw a similar set on Smogon and this pic came with the set. XD
On-topic, I would definitely recommend putting in hazards into this team, because things like Nidoking and Thundy are gonna be counting on them to hit some important KOs. There's a lot to choose from, but I would recommend standard Spikes (or SR) Skarm due to its synergy with Chansey. Well, good luck with this!