There's nothing we have yet to pay! (3)
I believe the answer is:
owe
'have yet to pay' is the definition.
(I've seen this in another clue)
'there's nothing we' is the wordplay.
'there's nothing' becomes 'o' (I've seen this in other clues).
'o'+'we'='OWE'
(Other definitions for owe that I've seen before include "Are debtors" , "Be in the red" , "Bear" , "Have a debt to (someone)" , "Have to thank" .)