I am surprised they were able to chip the side window glass. Tempered glass is quite hard to damage or break, and usually if you do manage to chip it, the whole window shatters.
I have never tried the DIY window repair, but as you say, it is worth a try, I doubt you could do any damage, the worst is likely the repair won't take, and fall out, it also may not be as clean/invisible as it is with laminated glass.
As for replacements, I would be looking at some of the wreckers that specialise in Nissan or import vehicles.. I am sure someone on here will jump in and give you a few options soon.