You basically said it in that last sentence. I've tried it out a bunch of times and not gotten far with it - it's too weak without Specs and dies without Sash. Boomburst is nice but gets blocked by Gengar and Aegislash, and virtually everything that's even a little bit common in the meta outspeeds and KOs (Kang, Thundurus, Garchomp, Blaziken, Gengar...). Heatran, Rotom and Tyranitar wall it and Chatter doesn't proc confusion enough to justify the low base power. Best to go with Mega Pidgeot if you want something that does the same thing but better.Is Chatot any good in singles? It's only #143 in usage, but that's still higher than some things in the viability rankings like Feraligatr, Omastar, and Kabutops.
It has a very strong STAB Boomburst(even a tiny bit stronger than Exploud's,) and another really good move in Chatter, which has a reasonable 65 BP and always causes confusion. Chatot also has some other really nice moves like Heat Wave, Encore, Taunt, and U-Turn.
But on the other hand it's ridiculously frail with 75/45/42 bulk, not much better than Sharpedo and worse than its mega. It's not that fast, and base 92 SpA is only kinda good. It's only ability that'd useful at all, Keen Eye, is also pretty situational and usually gonna do nothing.