I dislike mandatory retirement ages for anything, as i am almost always against lumping any group of humans all together as "all just the same".<-----almost invariably a mistake to do this.
I think older nurses, should be evaluated just like any other nurse-----------based upon her performance, etc. If a nurse, of any age, is having problems, well, those problems need to be addressed, or the nurse has to be let go,
but, i don't see the connection between a nurse having gray hair, and not being able to be an awesome nurse. I don't like "agism" and i suggest each and every nurse,
regardless of her hair color,
be evaluated based upon on her or his performance.
None of the things that the OP lists as "effects of aging" are specific to ONLY older people:
//(such as decrease in vision, hearing, unsteady gait, ect.) //
Any and all of those things can strike various humans at various ages. A nurse of any age, can easily perform well even if she is nearsighted or slightly hard of hearing, using glasses, surgery, or hearing aides, etc.
Even handicapped nurses, of any age, who can not walk well, can occasionally find areas of nursing where they can still nurse.