First post here. I am new to the battle tree but I have been lurking for a while and I used a team very similar to one of VaporeonIce's teams from Battle Maison to get to 200 wins in the Battle Tree Super Singles. Team is here:
http://www.smogon.com/forums/threads/battle-maison-discussion-records.3492706/page-155#post-6339607, though I can repost it on here if wanted.
Proof here:
I thought that I would contribute with this team as I think that it is a very safe, albeit slow method of getting to 200 wins.
I basically used the same exact team, except I used Flamethrower instead of Seismic Toss since it isn't available on Chansey. My logic is that Flamethrower is good enough coverage on some of the things that I am weak to and that Chansey can't toxic in the worst case scenario where I don't have Salamence or Aegislash to cover me.
When you get used to the play style, I think this team can stall out or set-up on just about anything. I am not the best player, so there were a few times that I had close calls, but I think this team can be piloted by just about anyone if they want those 200 wins, it will just take a long time.
I have seen a similar team with Chansey having Sub and Minimize, but I personally didn't like not having any offensive moves and I also didn't like having to keep Chansey in. In a whole lot of games that I was toxic stalling, I would switch back and forth between Chansey and Aegislash/Salamence. On the other hand, it could probably be argued that with Minimize and Sub, I wouldn't need to switch. I seriously considered switching to minimize/sub at about 150 wins, but decided against changing stuff up while I was still going strong.
I actually lost a previous run at 157 due to me not paying attention and getting Chansey and Aegislash wiped by a Contrary Lurantis.