Yee :3
OK lemme explain.
First, Chandelure is fairly common in VGC (Series 6), with these stats:
Monthly Usage
42k
Usage Percent
4%
Monthly Rank
#43
So yeah you can already tell a little bit that's it's viable from just its sheer usage stats.
In my opinion, the main reason to use Chandelure is to shut down Trick Room teams and prevent Protect. How? Imprison. With Imprison + Trick Room + Protect, it has a great niche in a Protect-filled metagame where TR team aren't that rare. Heat Wave can be used for spread damage STAB, and with Imprison it targets most Charizard and some Talonflame sets. Flash Fire allows it to switch into Charizard's Heat Wave and Talonflame's Flare Blitz, as well as Arcanine's Will-O-Wisp.
Chandelure is also a great choice for Trick Room teams, Imprisoning the opponent's Trick Room, allowing it to set Trick Room up without worrying about it being reversed.
As far as sets go, here are the the most common teammates / moves / items / abilities / EV spreads for Chandelure:
Shadow Ball GHOST 92.718%
Heat Wave FIRE 83.188%
Trick Room PSYCHIC 78.569%
Protect NORMAL 49.058%
Energy Ball GRASS 31.677%
Imprison PSYCHIC 25.565%
Burning Jealousy FIRE 14.891%
Ally Switch PSYCHIC 7.118%
Other 17.217%
Braviary NORMAL FLYING 23.084%
Clefairy FAIRY 21.804%
Corviknight FLYING STEEL 19.163%
Raichu ELECTRIC 18.584%
Terrakion ROCK FIGHTING 15.785%
Rotom-Wash ELECTRIC WATER 15.577%
Porygon-Z NORMAL 15.552%
Hatterene PSYCHIC FAIRY 14.009%
Azumarill WATER FAIRY 10.544%
Conkeldurr FIGHTING 9.300%
Toxtricity ELECTRIC POISON 8.496%
Jellicent WATER GHOST 2.893%
Focus Sash 47.694%
Colbur Berry 12.670%
Safety Goggles 12.424%
Weakness Policy 10.657%
Choice Scarf 7.096%
Life Orb 4.998%
Other 4.462%
Flash Fire 87.074%
Infiltrator 12.512%
Flame Body 0.413%
Timid 4/0/0/252/0/252 14.137%
Modest 252/0/4/68/4/180 11.043%
Modest 100/0/0/252/0/156 8.752%
Timid 0/0/0/252/4/252 5.901%
Modest 4/0/0/252/0/252 5.623%
Timid 132/0/4/204/4/164 5.315%
So, yeah. While Imprison doesn't seem to be the most common set, I feel like if your team is filled with fast sweepers, it is the best option. If you need a sweeper, maybe try Shadow Ball / Energy Ball / Heat Wave / Burning Jealousy with a Choice Scarf. Point is, the moveset depends on what your team needs.
So, yes, I would say that Chandelure is viable in VGC. It can play different roles depending on your team, and Imprison + Trick Room is a great niche, in my opinion.
Source
Hope this helps! :)
