Some of Horatio Nelson's quota (6)
I believe the answer is:
ration
'quota' is the definition.
(I've seen this before)
'some of horatio nelson's' is the wordplay.
'some of' indicates the answer is hidden within the clue.
'RATION' can be found hidden inside 'horatio nelsons'.
(Other definitions for ration that I've seen before include "Restrict the consumption of something" , "Food apportionment" , "Portion, share" , "Limit issue" , "Wartime allowance?" .)