it might help you to think that a nursing plan of care is developed from the nursing diagnoses you come up with from your nursing assessment, in a parallel way to how the medical plan of care is developed from the medical diagnosis obtained from the medical work-up. but there is no list of medical diagnoses with a second column for associated nursing diagnoses. nursing develops nursing diagnoses from nursing assessments.
some data may overlap from the medical assessment. for example, the medical diagnosis of anemia is made by looking at blood work that tells the physician about a shortage of (usually) red blood cells. one associated nursing diagnosis might be fatigue, since deficient red cells mean there is less oxygen to deliver to the body. another might be activity intolerance, for the same reason. however, some people tolerate anemia pretty well and may not exhibit characteristics of either of these, so you can't just say, "hmmm, medical diagnosis = anemia, must include activity intolerance in my care plan," because, well, maybe not. the physician has done the medical assessment; you have to do a nursing assessment.
as another example, if i admit a 55-year-old with diabetes and heart disease, i recall what i know about dm pathophysiology. i'm pretty sure i will probably see a constellation of nursing diagnoses related to these effects, and i will certainly assess for them-- ineffective tissue perfusion, activity intolerance, knowledge deficit, fear, altered role processes, and ineffective health management for starters. i might find readiness to improve health status, or ineffective coping, or risk for falls, too. these are all things you often see in diabetics who come in with complications. they are all things that nursing treats independently of medicine, regardless of whether a medical plan of care includes measures to ameliorate the physiological cause of some of them. but i can't put them in any individual's plan for nursing care until *i* assess for the symptoms that indicate them, the defining characteristics of each.
so, have you read in your med-surg text about common presentations for cva and what nursing would to assess them and then care for them? what observations did you make of your patient?