I agree with the poster above. The nursing significance of an abnormal chest x-ray could be the potential for ineffective gas exchange or ineffective airway clearance. It basically impairs the human need for breathing. And in terms of CPOD, it probably shows lung consolidation consistent with other data such as ronchi and tachypnea, etc.
If you have assessed your patient, THEN you look up nursing diagnoses by correlating the defining characteristics with your assessment findings. You don't pull nursing diagnoses off a list based on a medical diagnosis, or a chest x-ray.
The significance of abnl findings on a COPD chest x-ray have more to do with the medical diagnosis than the nursing diagnosis. I don't believe you'll find chest x-ray on the list of defining characteristics for nursing diagnoses you might see in the COPD patient, though if you have perused your NANDA-I 2012-2014 and find some, I am very happy to be corrected.