That's a fairly broad question... Your scope of practice is defined by your skills & knowledge combined with your hospital policy and procedure. There isn't a list of skills that you can and cannot do.
For example - at my hospital, Registered nurses can nurse initiate up to 2 doses of paracetamol, Coloxyl & senna, anti-acids, saline nebs, lice treatment and non-prescription topical creams. However Registered nurses working in ED are not allowed to nurse initiate - so for that department, it isn't within the nurse's scope of practice.
Whereas a nurse working in a rural/remote area, especially if they are running a remote health clinic can (with appropriate training & education etc) prescribe a far larger array of medications, such as more complex pain relief, anti-biotics etc - but if that nurse where to move to a city hospital it would no longer be within their scope to prescribe these medications.
IV cannulation is not within the scope of practice of a graduate nurse however most hospitals will have a training & education process for a nurse to become IV cannulation competent if that is a skill required in the area that they work in. However, this doesn't automatically mean that if that nurse moves to another hospital they will be classified IV cannulation competant there.