Japanese ruler OK amid chaos (6)
I believe the answer is:
mikado
'japanese ruler' is the definition.
(I've seen this before)
'ok amid chaos' is the wordplay.
'chaos' indicates anagramming the letters.
'ok'+'amid'='okamid'
'okamid' anagrammed gives 'MIKADO'.
(Other definitions for mikado that I've seen before include "mperor" , "Japanese emperor as in G & S operetta" , "Musical emperor of Japan" , "Japanese 2" , "Gilbert and Sullivan opera" .)