Like Officer Jenny, there is little difference among the Nurse Joy’s of pokemon. There are the small differences though, which is more than what can be said about the officer jennies; like in one of the orange islands episodes, one of the nurse joy’s had a really dark tan. Nurse joy’s helping pokemon typically tends to be a chansey, as chansey tend to come across as caring pokemon and are specifically trained to work at pokemon centers with nurse joy. There is the one exception, however, in one of the jhoto episodes where nurse joy is seen with a clumsy blissey (thats close enough though, as blissey is chancey’s evolution).
Nurse joy is a very caring person and always seems very willing to take care of sick and injured pokemon. In that same orange islands episode, it shows that she cared so much for a measley magikarp, that the magikarp evolved into gyarados, which still loved her and saved them from team rocket (everyone knows gyarados are difficult to train).
One exception to the sweet and sensitive side of nurse joy is the nurse joy from the majorly poluted city in which ash caught his muk. It was late at night when ash brought pikachu to the pokemon center, when nurse joy explained to ash that it probably just has a cold. But the way she explained it made ash feel like she just didint even care. But it was late at night, in a crappy city, so we can understand.