Final answer:
The priority nursing diagnosis for an infant with exstrophy of the bladder is Risk for infection.
Step-by-step explanation:
For an infant born with exstrophy of the bladder but otherwise appears healthy, the priority nursing diagnosis would be Risk for infection. Exstrophy of the bladder is a congenital abnormality where the bladder is turned inside out and exposed externally. This poses a high risk of infection as the urinary system is not functioning properly and the bladder is exposed to external contaminants. Infections can lead to further complications and should be closely monitored and prevented.