Foreign character, American in Illinois, checks onset of shooting from the hip? (7)

'foreign character american' is the definition.
The definition suggests an adjective which matches the answer.

'illinois checks onset of shooting from the hip?' is the wordplay.
'illinois' becomes 'IL' (abbreviation).
'checks' means one lot of letters goes inside another (inserted letters are checked or controlled).
'onset of' suggests taking the first letters.
'from the hip?' becomes 'chia' (I can't justify this - if you can you should give a lot more credence to this answer).
The first letter of 'shooting' is 's'.
's'+'chia'='schia'
'il' going around 'schia' is 'ISCHIAL'.

'in' is the link.

Can you help me to learn more?