Air Canada has Japan on sale with LAX to Nagoya NGO at $469 round trip for limited August-September departure dates. Las Vegas to Nagoya is priced at $492 round trip on Air Canada website.
Las Vegas seems to have better schedules with short layovers in Vancouver compared to long overnight layover outbound on LAX flights. Could be good if you want to sightsee in Vancouver, but unnecessary hotel expense if you don’t.
Momondo.com shows fares as low as $394 to $412 round trip from Las Vegas to Nagoya, but that deal appears to be fading. I only see it on select OTA sites now, when it was on Expedia earlier.
Mon Sep 4 Los Angeles LAX – Vancouver YVR (16h10m layover 20:35-12:45) – Nagoya NGO arrive 15:15 Wed Sep 6
Tue Sep 12 Nagoya NGO – Vancouver YVR – LAX
Mon Sep 4 Las Vegas LAS – Vancouver YVR – Nagoya NGO arrive 15:15 Wed Sep 6
Tue Sep 12 Nagoya NGO – Vancouver YVR – Las Vegas LAS