So, a nicer new storyline (8)
I believe the answer is:
scenario
'storyline' is the definition.
(I've seen this before)
'so a nicer new' is the wordplay.
'new' indicates anagramming the letters.
'so'+'a'+'nicer'='soanicer'
'soanicer' anagrammed gives 'SCENARIO'.
(Other definitions for scenario that I've seen before include "Master plan" , "Outline of film, novel, etc" , "Story outline" , "Event postulation" , "Dramatic set-up" .)