Rejected a ham omelette, initially, in Nebraskan city (5)
I believe the answer is:
omaha
'nebraskan city' is the definition.
(I've seen this in another clue)
'rejected a ham omelette initially' is the wordplay.
'rejected' says the letters should be written backwards.
'initially' indicates taking the first letters.
The first letter of 'omelette' is 'o'.
'a'+'ham'+'o'='ahamo'
'ahamo' back-to-front is 'OMAHA'.
'in' acts as a link.
(Other definitions for omaha that I've seen before include "- - Beach (WWII)" , "American town" , "Largest city in Nebraska" , "place in Nebraska" , "Nebraska city and code-named beach of D-Day landings" .)