Director touched by letter from Greek national (7)
I believe the answer is:
chilean
'director touched' is the definition.
I can't tell whether this definition defines the answer.
'letter from greek national' is the wordplay.
'letter' becomes 'chi' (chi is a kind of letter of the alphabet).
'from' is a charade indicator (letters next to each other).
'greek national' becomes 'lean' (I am not sure about this - if you are sure you should believe this answer much more).
'chi'+'lean'='CHILEAN'
'by' is the link.
Can you help me to learn more?
(Other definitions for chilean that I've seen before include "from South American country" , "foreign character" , "Nationality of citizen of Santiago" , "From e.g. Valparaiso" , "From Santiago, say?" .)