Hmm! Aye! That could cause chaos! (6)
I believe the answer is:
mayhem
'chaos' is the definition.
(I've seen this in another clue)
'hmm aye that could cause' is the wordplay.
'hmm aye' anagrams to 'MAYHEM'.
However, I am not clear how this is indicated.
Can you help me to learn more?
(Other definitions for mayhem that I've seen before include "Much trouble when" , "Big trouble!" , "Chaos, violent disorder" , "State of great confusion and disorder" , "violence" .)