Melody making cast end in chaos? (7)
I believe the answer is:
descant
'melody' is the definition.
(I have seen 'Upper melody ' mean 'descant' so perhaps 'melody' could also mean 'descant')
'cast end in chaos?' is the wordplay.
'in chaos?' indicates anagramming the letters (I've seen 'in chaos' mean this).
'cast'+'end'='castend'
'castend' is an anagram of 'DESCANT'.
'making' is the link.
(Other definitions for descant that I've seen before include "Sung variation" , "Melody sung or played above a basic melody" , "Highest range (eg of a 10)" , "Upper melody" , "Ornamental melody added above a theme" .)