More upbeat nurse in shot (7)

I believe the answer is:

sunnier

I'm a little stuck... Click here to teach me more about this clue!

'more upbeat' is the definition.
Both the answer and definition are comparative adjectives. Perhaps there's a link between them I don't understand?

'nurse in shot' is the wordplay.
'shot' is an anagram indicator.
'nurse'+'in'='nursein'
'nursein' anagrammed gives 'SUNNIER'.

Can you help me to learn more?

(Another definition for sunnier that I've seen is " Better weather".)

I've seen this clue in The Daily Express.

Want a hint initially instead of a full solution? Install my app