Someone else opened a thread over a year ago. You might inquire with that person to see if they made any progress
FYI: After doing a search, it appears that this is a Honeywell Thermostat. Find the actual model number versus what NV Energy rebranded it as.
And if you can find the specs, that would be even more helpful. It might show the Zigbee protocol it’s using. I couldn’t find it, so if they sent it with the Thermostat, share it with the community.