Pickled eggs from the east a big hit (6)
I believe the answer is:
'pickled' is the definition.
(I've seen this in another clue)
'eggs from the east a big hit' is the wordplay.
'eggs' becomes 'nits' (nits are insect eggs).
'from the east' shows that the letters should be reversed in order (on a map from right to left).
'a big hit' becomes 'KO' (knock out blow in boxing).
'nits' written backwards gives 'stin'.
(Other definitions for stinko that I've seen before include "Tight" , "one over the eight?" , "Drunk" , "worse for wear" .)