Help needed with automation Nest + Classic app

I want to set a humidifier hooked to a smart outlet that will power on when the humidity reading on my Nest thermostat goes below 50%. I tried smart lighting but it did not allow me to utilize the Nest humidity reading. I am using the NST Manager but I don’t see how to add the humidity reading as a trigger. I am not good with Webcore, so that is not an option. Any help would be appreciated.