Wolves after kill in America — this could be a chiller (3,4)
I believe the answer is:
ice pack
'this could be a chiller' is the definition.
(an ice pack keeps cool or chills)
'wolves after kill in america' is the wordplay.
'wolves' becomes 'pack' (pack of wolves).
'after' says to put letters next to each other.
'kill in america' becomes 'ice' ('ice' can mean to kill in US English).
'pack' put after 'ice' is 'ICE-PACK'.
(Other definitions for ice pack that I've seen before include "polar region" , "Used to reduce swelling" , "Cold bag for e.g. swelling" , "This could reduce swelling" , "Cooling application" .)