Aliens after chilly cuts of meat (8)
I believe the answer is:
briskets
'cuts of meat' is the definition.
(I've seen this in another clue)
'aliens after chilly' is the wordplay.
'aliens' becomes 'ETs' (ET is short for extraterrestrial).
'after' says to put letters next to each other.
'chilly' becomes 'brisk' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'ets' after 'brisk' is 'BRISKETS'.
Can you help me to learn more?
(Another definition for briskets that I've seen is " Cuts of beef found to risk bets".)