The strategy has some potential, but has way to many flaws. Will-O-Wisp takes a single moveset which allows for a stronger STAB Fire type move. If you give Chandelure a Wide Lens, all moves will have its accuracy raised. This means moves such as Fire Blast and even Will-O-Wisp will hit more often. In terms of Ability, Infiltrator allows it to burn and attack Pokemon past substitutes, stopping many stalling strategies. Adamant is not a very good nature, I recommend you use Modest or Timid. Chandelure's HP is way too bad to be useful, I'd say you should go for max Special Attack and Speed investment.
Chandelure @ Wide Lens / Air Balloon / Choice Scarf
EVs: 252 Spe / 252 SpAtk / 4 HP
Nature: Modest / Timid
- Fire Blast / Flamethrower
- Shadow Ball
- Dark Pulse / Energy Ball
Fire Blast is the most powerful STAB Fire move that doesn't have a negative side effect. With Wide Lens, it reaches an accuracy of ~94%. This allows it to hit with some consistency, however if you prefer Flamethrower or you aren't using the Wide Lens, go for Flamethrower. Will-O-Wisp is surprisingly effective. It stops Sucker Punch from Mega Kang and can cripple it in the process. With Infiltrator this can hit through substitutes and cripple anything that is attempting a stall. Will-O-Wisp also has an accuracy of ~94%, the same as Fire Blast, under a Wide Lens boost. Shadow Ball is a powerful STAB move that requires no accuracy boost, and can counter other Ghost types and Psychic types which carry a Dark or Ghost move. Dark Pulse is for coverage, and can hit Pokémon that usually resist its other moves. Energy Ball can hit Water types for super effectiveness, however cannot usually pick up needed KOs.
Max Speed and Special Attack investment to quickly devour everything in demonic flames. With Choice Scarf, Chandelure can outpace a surprisingly large portion of the unboosted metagame. Nothing else to really say here.
Wide Lens is the preferred item, boosting Fire Blast and Will-O-Wisp's accuracy to consistent and decent levels. Air Balloon can be used to remove the Ground weakness, and to help an ally use Earthquake more often. However once hit Chandelure loses this Ability and the item will have often failed. Choice Scarf can boost Chandelure's Speed to high levels, but shouldn't be considered above the formentioned items.