South American chain oddly missing this dish (5)
I believe the answer is:
sushi
'this dish' is the definition.
(sushi is a kind of dish)
'south american chain oddly missing' is the wordplay.
'south' becomes 'S' (abbreviation).
'american' becomes 'us' (abbreviation for United States).
'oddly missing' indicates alternate letters (letters in odd-numbered positions removed).
The alternate letters of 'chain' are 'hi'.
's'+'us'+'hi'='SUSHI'
(Other definitions for sushi that I've seen before include "Fated" , "Cold rice balls with raw fish" , "Rice, seafood cuisine" , "Cold rice dish, often with raw fish" , "exotic dish" .)