Nest Hello Has Power but Doesn't (Often) Ring Indoor Chime?
I had a similar issue. Originally the indoor doorbell chime rang, then it stopped ringing the day after install. I found that the reason was that the white Nest connector wires that I added in the chime we’re getting in the way of the electro mechanical solonoid. They were preventing the movement. Once I moved the wires out of the way it started ringing again.

One other thing- there is a setting called Indoor Chime On/Off. If Off, then the indoor chime won’t ring but the Nest doorbell itself will make a bell sound.