I tried using a 2nd mac and had the same problem. Unfortunately, with the Nest router, it is not possible to switch my mac to using the 2.4 GHz band (at least not that I can see). But the Epson printer also uses the 2.4 GHz band so that cannot be the whole story. I read on the internet that the problem could be that a printer using the 2.4 GHz band would not talk to a device on the 5 GHz band and indeed the HP printer is on the 2.4 GHz band and my mac is using the 5 GHz band. I am able to ping the Epson printer but not the HP printer (I get 'Request timeout' messages). I also have an Epson WorkForce 630 printer on this wi-fi network which I can print to. When I use the command 'arp -a' from my mac I can see the printer: mac-mini-2:~> arp -a The mac was aware of the printer (it listed the printer in the list of possible devices to add) but when I tried to add it I got the error message: Unable to connect to 'HP Officeject Pro 8610. Turn off or disable the Automatically Update Check function. I tried removing and then reinstalling the printer to the printer list on my mac. Make sure your printer is in good condition.
The printer is connected to wi-fi with a valid IP address (196.168.86.5). I used to be able to print to my HP Officejet Pro 8610 printer until I upgraded my wi-fi to using a single dual-band AC2200 Nest router.
