Level 100 Statistics (see level 5, 50, 100)
At first glance, Chatot may appear to be another throwaway joke Pokemon in the vein of Farfetch'd and Delibird, but a closer look reveals some pleasant surprises: base 91 Speed makes Chatot faster than many of UU's biggest threats, and with Nasty Plot to boost its respectable Special Attack, Chatot can become a legitimate offensive threat. It can't take a hit to save its life and needs major support to succeed, but don't underestimate this musical bird.
Chatot may not look like much of a threat, but if it manages to obtain a Nasty Plot boost, it will be dishing out some serious damage. A boosted STAB Hyper Voice will OHKO most offensive Pokemon, including Life Orb Venusaur and Arcanine, while 2HKOing even special walls such as Milotic and Clefable. Heat Wave provides solid coverage, hitting most of the Ghost- and Steel-types that resist Hyper Voice for at least a 2HKO after a boost. Encore is recommended in the last slot to help Chatot set up, as the frail bird will otherwise have difficulty finding an opportunity to use Nasty Plot. Hidden Power Grass is an alternative to hit Rock-types such as Rhyperior, Kabutops, and Omastar for 4x super effective damage, but it's usually unnecessary, as all three are 2HKOed by boosted Hyper Voice anyway.
Team Options & Additional Comments >>>
A Choice set allows Chatot to take advantage of its nice offensive stats without needing to set up. Choice Specs boosts Chatot's decent Special Attack stat to an excellent 424, whereas a Choice Scarf makes it faster than any unboosted Pokemon in UU. Hyper Voice is Chatot's most powerful STAB move and has great neutral coverage. Heat Wave fries the Steel- and Ghost-types that resist Hyper Voice, while Hidden Power Grass rounds out the coverage by hitting Rock-types hard. In the last slot, U-turn is always a useful move on a Choice set to scout for counters and maintain momentum, although it won't be doing much damage off Chatot's pathetic Attack stat. If U-turn doesn't appeal to you, Chatot's signature move, Chatter, is also an option; although its low Base Power is disappointing, it hits Fighting-types harder than Chatot's other moves and packs a handy 31% confusion rate.
Team Options & Additional Comments >>>
Chatot's movepool is rather barren; the only worthwhile attacks not already mentioned are other types of Hidden Power. Hidden Power Water provides perfect neutral coverage with Hyper Voice if Chatot is only using two attacks, but it is significantly less powerful than Heat Wave against Steel- and Ghost-types. Hidden Power Ground hits both Rock- and Steel-types, and is Chatot's best option against Aggron.
Substitute or Taunt can be used with Nasty Plot to protect Chatot from status, although neither is capable of generating free turns as reliably as Encore. Agility is an alternative boosting move, but Chatot's Speed is already very respectable, so boosting Chatot's power with Nasty Plot is generally more important. FeatherDance and Roost are nice moves on defensive Pokemon, but Chatot doesn't have nearly enough bulk to use them effectively. Tailwind would be a cool support move if it lasted longer, but with only two exploitable turns, it is essentially an inferior Agility. Sing can put a counter to sleep and give Chatot a free turn to set up, but its terrible accuracy makes it a huge risk that Chatot can rarely afford to take.
Checks and Counters
Unfortunately, Chatot is so frail that any faster Pokemon it can't OHKO is essentially a counter. Mismagius is immune to Hyper Voice, can survive a Nasty Plot-boosted Heat Wave, and easily OHKOes Chatot with Thunderbolt. Choice Band Spiritomb can do the same with Sucker Punch, although it must beware of Chatot Encoring and then setting up on Sucker Punch. Though rare, Life Orb Electrode can switch in on Hyper Voice freely thanks to Soundproof and wreck Chatot with its STAB Thunderbolt. Arcanine, Scyther, Sceptile, and any other offensive Pokemon that hits 310 Speed or above can come in as Chatot sets up and OHKO it before it gets the chance to attack. Chansey walls Chatot's attacks easily, but it must beware of being turned into set-up bait by Encore. Stealth Rock makes Chatot even easier to take down; after switching into Stealth Rock once, Chatot can be OHKOed by even neutral STAB attacks from defensive Pokemon.