A chance to offer support (4)
I believe the answer is:
abet
'support' is the definition.
(I've seen this before)
'a chance' is the wordplay.
'chance' becomes 'bet' (I've seen this in another clue).
'a'+'bet'='ABET'
'to offer' is the link.
(Other definitions for abet that I've seen before include "helpful" , "Give aid to" , "Assist in some nefarious activity" , "Aid in offence" , "Assist criminally" .)