Busy chef acts nice, avoiding extremes (6)
I believe the answer is:
hectic
'busy' is the definition.
(thesaurus)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for hectic that I've seen before include "Involving feverish activity, chaotic" , "Extremely busy - fevered" , "Marked by intense agitation - fevered" , "Frenzied" , "Agitated and rushed" .)