Politoed@Leftovers / Chesto Berry
EVs: 248 HP 16 SpA 244 SpD
-Ice Beam/Perish Song/Rest
A reasonable stop to Chandelure (not counter because it doesn't have reliable recovery), given the following calcs:
252 SpAtk Chandelure Shadow Ball vs 252 HP/252 SpDef Politoed (+SpDef) : 26.56% - 31.51% : 4-5 hits to KO (with Leftovers)
Meanwhile, with 16 SpA evs Politoed can ohko Chandelure with Scald in the rain, and even if Chandy has a sub up, it is forced out.
(Note that if the team with Chandelure is running opposing weather, Politoed will be severely weakened, so a ChestoRest set is also an option)
Toxic allows Politoed to hit Keldeo, Chomp, Ttar, Loom, etc. on the switch, and Protect helps Politoed gain extra leftovers recovery as well as scout for Genesect's move and so forth.
Ice Beam is mainly filler, but can nail Garchomp on the switch for huge damage (81.56%-97.21%), but Perish Song is an option to stop Manaphy or something else on the switch in.