Senior nurse nursing home finds menacing (8)
I believe the answer is:
sinister
'menacing' is the definition.
('sinister' can be a synonym of 'menacing')
'senior nurse nursing home' is the wordplay.
'senior nurse' becomes 'sister' (I've seen this before).
'nursing' indicates putting letters inside.
'home' becomes 'in' ('he's home' can mean 'he's in').
'sister' placed around 'in' is 'SINISTER'.
'finds' acts as a link.
(Other definitions for sinister that I've seen before include ", nun going round home" , "Menacing" , "Forbidding" , "Eerie, alarming" , "Suggestive of evil/harm" .)