Unity makes a nice change for everybody (8)
I believe the answer is:
alliance
'unity' is the definition.
(thesaurus)
'a nice change for everybody' is the wordplay.
'change' is an anagram indicator.
'for' means one lot of letters go next to another (I've seen this in other clues).
'everybody' becomes 'all' (I've seen this before).
'a'+'nice'='anice'
'anice' is an anagram of 'iance'.
'iance' put after 'all' is 'ALLIANCE'.
'makes' is the link.
(Other definitions for alliance that I've seen before include "Bond" , "Kind of partnership with canaille" , "A joining of forces" , "Formal agreement" , "Combination by treaty" .)