Had nice duty to broadcast, as historian (11)
I believe the answer is:
thucydidean
'historian' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'had nice duty to broadcast' is the wordplay.
'to broadcast' indicates an anagram (letters scattered or cast around).
'had'+'nice'+'duty'='hadniceduty'
'hadniceduty' anagrammed gives 'THUCYDIDEAN'.
'as' is the link.
Can you help me to learn more?
(Another definition for thucydidean that I've seen is " Relating to an early Greek historian".)