I'm sorry but I have to agree with Chrona's point.
ST Chandy is, in my view, overpowered in OU. The comments I've seen about 'switching is related to the skill of the battler' is rubbish (no offence meant). Anyone running a Choiced Set on an ST Chandelure at least half knows what they're doing, and would be stupid to NOT switch it out from a pokemon that counters it. Pursuit users are capable of dealing with it, and perhaps solid sp.def walls like Blissey could take it's hits and outstall it (to which you'd most likely see a switch before that happened).
On the flip-side however, what if it ISN'T choiced? Non-choiced ST Chandy could potentially be dealt with quite easily due to it's low speed stat (since it would lack the speed to be a fast revenge killer), but again that leaves the chance of the opponent switching out Chandelure from the counter, which is highly likely.
Basically the thing with Chandelure is that you need at least two pokemon to deal with it (unless you have very good prediction). One has to be sacrificed to allow the counter to come in. But as has been said, 90% of people using ST Chandy (especially those FROM THIS SITE, whom the tiers are mostly made for) know how to use it and to switch out when a counter pops up, thus rendering that idea almost completely null and void.