Come up very nicely (5)
I believe the answer is:
swell
'come up' is the definition.
The definition and answer can be both related to change as well as being verbs in their base form.
Maybe you can see a link between them that I can't see?
'very nicely' is the wordplay.
'very' becomes 's' (I can't explain this - if you can you should give a lot more credence to this answer).
'nicely' becomes 'well' (I've seen this before).
's'+'well'='SWELL'
Can you help me to learn more?
(Other definitions for swell that I've seen before include "slow rise and fall" , "First class" , "Informally good, grow larger" , "part of organ" , "Person of high social standing" .)