Is PORT recommended for incidentally found N2+ NSCLC after lobectomy for oligoprogressive metastatic NSCLC?

I would say it should probably be used very selectively in this population.  

We routinely use PORT for stage 3 patients who have incidentally discovered N2 nodes, but I try to keep in mind that that evidence supporting its use is not strong, even in the curative setting.  There's a consistent LC benefit, but the potential OS benefit seems to be partially or completely offset by the toxicity of the radiation.  

In the oligoprogressive population, the vast majority of patients will ultimately progress distantly regardless of their local control, so I would think the benefit here would be smaller.  And the presence of the N2 nodes suggest the risk of occult disease is particularly high.

The more important lesson of a case like this is that if this patient's mediastinum were staged positive with EBUS or med before surgery, I would have recommended a non-surgical approach in the first place.

Oligoprogressive metastatic NSCLC includes an extremely wide range of patients with different prognoses, and there are certainly many patients who would benefit from aggressive local therapy, including PORT.  The duration of response to prior therapy, the number and distribution of distant metastatic disease at diagnosis, the durability of response off systemic therapy, and the likelihood of control with future systemic therapy (I'm thinking of targetable mutations in particular) should all be carefully considered.