If you have a hard time getting your head around the difference, please do this. STOP all use of the word "orders." It is an anachronism left over from when nursing services were beginning to be formalized, and much of that occurred in military (war) settings.
There is a medical plan of care, and a nursing plan of care. Physicians are the only ones licensed to prescribe certain things, like medications, invasive procedures, and many other things. Nurses are legally obligated to implement some of the medical plan of care, but not all, obviously, right? Lab, dietary, PT... not nursing. Nurses are also obligated not to implement any part of a medical plan of care that we know will be injurious to the patient. This is, partly, why the concept of "following orders" is not a functional way to look at our collaborative practice.
The other reason to differentiate between the medical plan of care and the nursing plan of care and eliminate the word "orders" from our relationship with physicians is that it makes people think we are too stupid and uneducated to have any autonomy. Nursing diagnosis is not some artsy-fartsy thing that eggheaded academics dreamed up to torture students with. It is a scientifically-validated framework for autonomous practice that defines all RNs' (not APRN or NP) responsibilities for independent prescription that others do not have, including physicians.
I hear you about not being able to do some tasks without physician prescription, because they are part of a medical plan of care which we are delegated to implement. But you will find in the real world that a plethora of standing prescriptions and algorithms will offer the experienced nurse all the opportunity for judgment in that regard that s/he can handle. Fear not, and stop whining about it.