Child of immigrant couple that is beginning to settle in after upheaval? (5)
I believe the answer is:
nisei
'child of immigrant couple' is the definition.
(US term for a child of Japanese immigrants)
'that is beginning to settle in after upheaval?' is the wordplay.
'that is' becomes 'ie' ('i.e.' can be a synonym of 'that is').
'beginning to' suggests taking the first letters.
'after upheaval?' says the letters should be written in reverse (in a down clue, letters go up).
The initial letter of 'settle' is 's'.
'ie'+'s'+'in'='iesin'
'iesin' in reverse letter order is 'NISEI'.
(Other definitions for nisei that I've seen before include "One born in the US of Japanese emigre parents" , "Type of American citizen" , "that's evil? The reverse" , "Child of immigrants" , "Japanese Canadian/American" .)