It might well be possible to replace the horizontal slats if that's all that's broken. For the most part the louvers are all "snap together" pieces, even the plastic ladders that angle them. Since only the driver's side is broken, you might want to buy a new assembly and try to dissect the passenger vent. You're out the cost of the assembly if you break it, but you'll save a ton if it works.
Btw, assuming it's similar to the Altimas, the whole dashpad won't need to come out. It just needs to be lifted enough to get a shorty phillips back there. That means the steering wheel won't need to drop and the console can be pushed back, not removed. Since the screws are awkward to get back in with a partial removal (especially the driver's side), I leave them out and use a very strong glue like Permatex Ultra Gray when I reinstall. Still a big job, but I don't think 7 hours' worth, and probably not beyond the reach of a talented backyarder.