Nerd can do wrong, with daughter going great guns (8)
I believe the answer is:
ordnance
'guns' is the definition.
(ordnance can mean guns or artillery)
'nerd can do wrong with daughter going great' is the wordplay.
I cannot really understand how this works, but
an anagram of 'can' is 'anc' which is present in the answer.
an anagram of 'nerd' is 'rdne' which is within the left over letters.
A single letter 'o' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for ordnance that I've seen before include "Anne Cord is in military supplies" , "type of armament" , "Heavy guns and military supplies" , "Mounted guns, cannon" , "guns etc." .)