A benefit adopted by North America produces disgust (6)
I believe the answer is:
'disgust' is the definition.
(nausea is a kind of disgust)
'a benefit adopted by north america' is the wordplay.
'benefit' becomes 'use' (I've seen this before).
'adopted by' is an insertion indicator (I've seen this in other clues).
'north america' becomes 'na'.
'ause' placed inside 'na' is 'NAUSEA'.
'produces' acts as a link.
(Other definitions for nausea that I've seen before include "Sickness, biliousness", "Sick feeling", "Squeamishness", "Feeling of revulsion", "Unpleasant feeling".)