Raids Asda or Nisa stores from the south (7)
I believe the answer is:
inroads
'raids' is the definition.
(inroad can mean a raid or attack)
'asda or nisa stores from the south' is the wordplay.
'stores' indicates the answer is hidden within the clue.
'from the south' says the letters should be written in reverse (in a down clue, letters go up).
'sdaorni' is hidden within 'asda or nisa'.
'sdaorni' reversed gives 'INROADS'.
(Other definitions for inroads that I've seen before include "Hostile incursions" , "advances" , "Making them is reductive" , "raid" , "Encroachments" .)