@browncoat - Well, that's the job though. I mean, either they are qualified to do it or they aren't. And most trials are double-blind now so the nurse won't have any control or knowledge of who is getting placebo and who isn't. Nurses fresh from university are often more passionate and have new ideas which is good.
But, I don't think most nursing research is trials anyway. I'd imagine the foundations of nursing research lie more in observation and gathering statistics than anything and aside from knowing the information gathering techniques that's not that different from standard nursing.