Bishop's nasty feud led to puzzle (8)
I believe the answer is:
befuddle
'puzzle' is the definition.
('befuddle' can be a synonym of 'puzzle')
'bishop's nasty feud led' is the wordplay.
'bishop' becomes 'b' (abbreviation used in chess).
'nasty' indicates anagramming the letters.
'feud'+'led'='feudled'
'feudled' is an anagram of 'efuddle'.
'b'+'efuddle'='BEFUDDLE'
'to' acts as a link.
(Other definitions for befuddle that I've seen before include "Discombobulate" , "Make stupid with drink" , "Make stupefied" , "Bewilder" , "Perplex" .)