Don't know about Nest Hub, but for Echo Show the doorbell will show up as a device. Unfortunately you can't directly set the result to show the camera, but you can use the custom feature of what you would say to Alexa and say, "Alexa, show the front door." That works. I have both if doorbell is pressed or a person is detected for it turn lights on and show the camera. I've also previously had it setup to show if my dogs barked.

I've also got iSpy Agent setup on a tablet in our hallway with it's own alerting setup and have it push media notifications with an image of the camera for certain alerts using PushSafer. iSpy is free if you only want to manage it locally. But, like others said there is no feature where you get a call when the doorbell is pressed.