Bringing up son — no good providing fruity nibbles? (7)
I believe the answer is:
raisins
'fruity nibbles?' is the definition.
(small fruit snacks)
'bringing up son no good' is the wordplay.
'bringing up' becomes 'raising' (raising is a kind of bringing up).
'son' becomes 's' (genealogical abbreviation for son).
'no' suggests deleting specific letters.
'good' becomes 'g' (abbreviation).
'raising'+'s'='raisings'
'raisings' with 'g' taken out is 'RAISINS'.
'providing' acts as a link.
(Other definitions for raisins that I've seen before include "Dried grapes, nice in cakes" , "Dried grapes used in cakes" , "Fruit that's dried" .)