Yes, you do talk to nurses, and the overwhelmingly vast majority of the time, they know more than you. Maybe they don't know the gene that causes a predisposition to a certain disease, but they know how to manage patients and provide patient care better than you, which is more important on the wards.
Nurses often provide valuable information about the patients. I just finished a shift in the ED and a nurse saved my butt on a patient, an unaccompanied 95 y/o delirious woman and an overall poor historian, but the nurse had gotten a good history from the patient's son on intake, so she told me what was going on.
You should always be confident in yourself, but it is not a medical student's place to contradict or challenge a nurse. Nurses aren't people you "have to deal with," they are vital members of the care team and will be a great asset to you as a medical student.