No, he and CNN can and probably will be sued. See current article on American Thinker.
A little known fact about these types of settlements is there is both a non-disclosure clause (i.e., neither side can announce the amount of settlement) and a non-disparagement agreement (neither side can make negative remarks about the other.)
Since Joe works for CNN, he should have been warned. Now the settlement may be voided and its back to court for CNN. Possibly more dough for Nick.
beyond that, I assume nick’s speech was run past his lawyer for this very reason.
curious to see where these various possible breaches end up. it may be cnn simply keeps writing checks and nothing is ever said publicly by either side.