Stun offering packs of snacks (5,4)

'packs of snacks' is the definition.
I know nothing about this answer so I can't tell whether this works.

'stun' is the wordplay.
I cannot really understand how this works, but
an anagram of 'stun' is 'nuts' which is present in the answer.
The remaining letters 'mixed' is a valid word which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).

'offering' is the link.

Can you help me to learn more?