Chap carrying leftover food up for head nurse (6)
I believe the answer is:
matron
'head nurse' is the definition.
(synonyms)
'chap carrying leftover food up' is the wordplay.
'chap' becomes 'man' (chap can mean a man).
'carrying' means one lot of letters goes inside another.
'leftover food' becomes 'ort' (as in orts, scraps of leftover food).
'up' is a reversal indicator (in down clue: letters go upwards).
'ort' backwards is 'tro'.
'man' enclosing 'tro' is 'MATRON'.
'for' acts as a link.
(Other definitions for matron that I've seen before include "Chief nurse" , "Old woman" , "Senior nurse" , "Medical supervisor" , "school officer" .)