Musical number with good numbers making a comeback ... (4)
I believe the answer is:
Here is my best explanation:
'musical number' is the definition.
(I've seen this before)
'with good numbers making a comeback' is the subsidiary indication.
'with' is a charade indicator (letters next to each other).
'good' becomes 'g' (abbreviation).
'numbers' becomes 'nos' (I've seen this in other clues**).
'making a comeback' is a reversal indicator.
'g'+'nos' is 'gnos'.
'gnos' in reverse letter order is 'song'.
(Other definitions for song that I've seen before include "Vocal composition", "Musical number", "Musical composition with words", "Piece of music, usually with words", "Ballad, aria", "Melody (which is cheap to go for)", "See 17", "Aria", "Vocal item" and "See 9".)