Nervous of operating something sharp (2,4)
I believe the answer is:
on edge
'nervous' is the definition.
(I've seen this before)
'operating something sharp' is the wordplay.
'operating' becomes 'on' (I've seen this in other clues).
'something sharp' becomes 'edge' (as in the edge of a blade).
'on'+'edge'='ON EDGE'
'of' is the link.
(Other definitions for on edge that I've seen before include "Fidgety, nervous" , "'Tense, nervous (2,4)'" , "Nervously excited" , "stressed" , "Cliff-top walker may be" .)