Nice gal - could be very good indeed (7)
I believe the answer is:
angelic
'good indeed' is the definition.
I can't judge whether this definition defines the answer.
'nice gal could be' is the wordplay.
'could be' is an anagram indicator.
'nice'+'gal'='nicegal'
'nicegal' with letters rearranged gives 'ANGELIC'.
'very' acts as a link.
Can you help me to learn more?
(Other definitions for angelic that I've seen before include "Virtuous" , "Of innocent beauty" , "Nice gal (anag.)" , "Seraphic, cherubic" , "Like heavenly beings" .)