Neal Adams cover is really the best thing about the concluding half of the Nova tale, by Bates, Ross Andru and Mike Esposito, in World’s Finest 180 (Nov. 68).
Nova has been captured, and is implanted by Mr. Socrates with a mind-control device, and then sent off to be used as a living weapon against Batman. So much for the super-hero career.
Superman sheds the Nova costume, although he does not regain the powers. He conveys to Batman that he is being controlled, and Batman creates a collar that blocks the signal.
The story ends with Superman giving up on being Nova, but Batman suggesting that he simply needs more training. It leaves the possibility of a follow-up story open. None ever came, but Nova is seen, possibly only once more. I remember noting him in the Hypertime montage in The Kingdom around the millenium.