Being nice means very little, in a way (5)
I believe the answer is:
sweet
'being nice' is the definition.
(thesaurus)
'very little in a way' is the wordplay.
'very little' becomes 'wee'.
'in' indicates putting letters inside.
'a way' becomes 'st'.
'wee' put inside 'st' is 'SWEET'.
'means' is the link.
(Other definitions for sweet that I've seen before include "Melodious, not bitter" , "Sugary - but might be tart!" , "Gentle" , "Having a sugary taste" , "Confection" .)