If you are referring to the line:
"It matters not a whit what I achieve. ...."
Then it is correct having the word "whit".

Whit means "a very small part or amount" and in the context of what Nero is saying, "It matters not a 'small amount of' what I achieve. ..." as he, at this point, is complaining to Cid that even though he considers himself a better Garlean than Cid, he is always seen as lesser than Cid.