Chaos as animal is getting right inside (7)
I believe the answer is:
misrule
'chaos' is the definition.
(thesaurus)
'animal is getting right inside' is the wordplay.
'animal' becomes 'mule' (I have seen 'Hybrid animal ' mean 'mule' so perhaps 'animal' could also mean 'mule').
'getting' says to put letters next to each other.
'right' becomes 'R' (common abbreviation).
'inside' means one lot of letters goes inside another.
'is'+'r'='isr'
'mule' placed around 'isr' is 'MISRULE'.
'as' is the link.
(Other definitions for misrule that I've seen before include "Unfair government; disorder" , "Disorder (lord of)" , "Bad government" .)