North America to deploy soldiers — they make one sick! (9)

I believe the answer is:

nauseants

'they make one sick' is the definition.
(substances causing nausea)

'north america to deploy soldiers' is the wordplay.
'north america' becomes 'na'.
'to deploy' becomes 'use' (I've seen this before).
'soldiers' becomes 'ants' (I've seen this before).
'na'+'use'+'ants'='NAUSEANTS'

I've seen this clue in The Guardian.

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