I have a Nest Hello and quite happy with the basic features within the Nest App. Due to the “works with nest” misery now some month ago, i was unhappy that my Homey did not had contact anymore with all of my Nest stuf (Hello, Thermostat, 2x Camera, 4x Fire / Smoke detector). At the moment i still have a dumb “gong” bell that will sound if someone rings the Nest Hello doorbell. It is quite a standard bell with two sound plates and a coil that bangs a piston to these sound plates.
I simply added a Xiaomi Aqara Vibration sensor to one of the sound plates. Now when the someone rings the door Homey will also know and I can start flows to automate stuff. At the moment not very fancy just testing if it never miss a ring. Later i will connect the Face++ App to my " future" Nuki (still waiting for a good deal somewhere)
here a some pics not fany but it works.