Nick and Jack facing trouble (4)
I believe the answer is:
jail
'nick' is the definition.
(British slang)
'jack facing trouble' is the wordplay.
'jack' becomes 'J' (playing card abbreviation).
'facing' says to put letters next to each other.
'trouble' becomes 'ail' (synonyms).
'j'+'ail'='JAIL'
'and' acts as a link.
(Other definitions for jail that I've seen before include "Nick" , "detention" , "Gaol" , "Clink" , "Correctional institution" .)