Get 371 combo on Normal difficulty or 447 combo on Hard difficulty Chatmonchy - Make Up! Make Up!
Sliders that are broken (not fully completed) won't let you get max combo even if you get an S. Don't break them.
EZ/DT/HR mods can be used (combining works too, like DTHR/EZDT). Doesn't work in Mania/CTB (taiko not tested).