Hello davejl,
Thanks for posting here in the Community. Based on the photos of the wires from your current thermostat, this is a heat pump system. This should be compatible with any type of Nest thermostat.
The correct wiring configuration for that in a Nest thermostat is the following:
Yellow wire on Y1
Red wire on RC or RH
Blue wire on C
Green wire on G
Orange wire on O/B
White wire on W1
The S1 and S2 wires are for outdoor temperature sensors, which you don't need since the Nest thermostat uses WiFi to get the outdoor temperature.
Let me know if you have more questions.
Thanks,
Edmond
