Facial feature fed nougat initially, same part spitting out old humbug (8)
I believe the answer is:
nonsense
'old humbug' is the definition.
'nonsense' can be an answer for 'humbug' (I've seen this before). I'm not certain of the 'old' bit.
'facial feature fed nougat initially same part spitting out' is the wordplay.
'facial feature' becomes 'nose' (part of the face).
'fed' means one lot of letters goes inside another (one word is 'fed' to another).
'initially' suggests taking the first letters.
'same part spitting out' becomes 'nse' (I can't justify this - if you can you should give a lot more credence to this answer).
The initial letter of 'nougat' is 'n'.
'nose' placed around 'n' is 'nonse'.
'nonse'+'nse'='NONSENSE'
Can you help me to learn more?
(Other definitions for nonsense that I've seen before include "Rubbish, drivel" , "Rubbish, foolish talk" , "Gobbledegook" , "folly" , "Claptrap, hogwash" .)