Not for nuthin' -- This is the New York City equivalent of "respectfully speaking" or "all-due respect", warning the receiver that they are about to get a dose of unvarnished truth that they might find insulting, but isn't meant to be insulting.
by pardon-my-new-york-accent September 29, 2022
It means “not for nothing”
by JB80 April 8, 2023
by MommyH2611 November 9, 2018