Expected to accommodate king or nobleman (4)
I believe the answer is:
duke
'nobleman' is the definition.
(duke is a kind of nobleman)
'expected to accommodate king' is the wordplay.
'expected' becomes 'due' (I've seen this before).
'to accommodate' means one lot of letters goes inside another.
'king' becomes 'k' (**).
'due' going around 'k' is 'DUKE'.
'or' acts as a link.
(Other definitions for duke that I've seen before include "Highest hereditary title in Britain" , "Nobleman - fist" , "Nobleman of the highest rank" , "Fist (sl.)" , "Highest rank of British peer" .)