Hi.
The report showed some lymph nodes. Likely they are reacting against something - whether the cause is benign or malignant is difficult to say.
In general lung cancers would show a mass in the lung itself, which would subsequently invade the mediastinal lymph nodes - if only the lymph nodes are showing up, and they are present on both sides- would make one think more of lymphoma rather than lung cancer.
It would be better to consult a doctor and look for any symptoms pertinent to the findings. It is possible that you may have a chronic infection in the lungs, other diseases affecting the immune system may have similar findings as well.
I see no harm in a second opinion.
Bear in mind though, that observation is a valid plan.
Stay positive.
light smoking is a risk for lung cancer, but subcentimeter mediastinal nodes means that there are lymph nodes smaller than 1 cm in your mediastinum which can be normal, but if you're not satisfied with the ARNP's explanation then you should ask questions until you're satisfied with the answers