The fact that this thing doesn't get Fake Out sucks. TechOrb'd Fake Out is great, although Ambipom is so closely related to this guy that it doesn't matter. My set for Chirachiino:
TechOrb
Adamant
6 HP/ 252 Attack / 252 Speed
@Life Orb
Technician
Chirachiino doesn't need max Speed at Base 115 unless your looking to revenge-kill (In which case, Choice Scarf is now your item and you replace Sweep Slap with Get Even [Vengence is a better name...anyway...]). You could opt for Rock Blast if you don't mind the Accuracy issue. Rock Blast + Wake-Up Slap provides excellent type-coverage, especially alongside Aqua Tail and Sweep Slap / Vengence. iirc, Chirachiino hits around 313 with max Attack, so this 'mon isn't bad at all when using TechOrb and those multi-hit moves. I give it a 4/5 overall.