Brave deeds can make riches out of nothing! (7)
I believe the answer is:
heroics
'brave deeds' is the definition.
(I've seen this before)
'make riches out of nothing' is the wordplay.
'make' indicates anagramming the letters.
'out of' is an insertion indicator (some letters on the outside of others).
'nothing' becomes 'O' (looks like zero - 0).
'riches' is an anagram of 'herics'.
'herics' placed around 'o' is 'HEROICS'.
'can' is the link.
(Other definitions for heroics that I've seen before include "Amazing feats" , "Brave deeds" , "Bold and fearless behaviour" , "Bold and dramatic behaviour" , "Unduly bold behaviour" .)