I'd go with NU. Significantly better overall prospects (biglaw, clerkships, etc.) trumps 80k in debt, especially for someone who doesn't seem to inclined to go into biglaw in the first place. it isn't like 130k is that manageable on a pi salary, although it is likely more manageable than 210k. if OP is serious about pi/government, then i think debt shouldn't be a factor given LRAP/IBR.
Again, while Boston is insular, I don't think they are insular for top candidates. all things being equal, i would imagine most employers would hire the NU candidate over the BU candidate, especially if OP has legitimate ties to Boston.
Main issue I see with BU is that it over performs in biglaw relative to its other placement, i.e. while it sends a good portion of its grads into biglaw, the non-biglaw grads have significantly worse prospects. i don't think this is the case at NU. Again, last year BU had 17% of its students working in "academia," which obviously is 17% working at a law school created fellowship simply to pump up its USNews statistics. That is practically 1 in 6 students...which is just awful for a T20 school. Given that OP has other options, I think it makes sense to go a different route.