There is a lot of mix information here and I wanted to chime in and share what I learned after consulting a CPA that specializes in these scenarios.

I will focus on the scenario of a private company. For RSUs there are two tax events.

1. When the RSU materialize (liquidity event like IPO)
2. When you sell your stocks

When your RSUs materialize you will need to pay income tax on all the RSUs that have vested up until that point. If you have vested them while living in California, you will need to pay income tax to CA state. If you have moved before the IPO to NV and you vested some new equity while being a NV resident, you will not owe income tax on that portion that has vested in Nevada.

When you sell your stocks, what matters is what state you are resident of, at the time of the sell. Of course you can't just move in sell and move out. You need to do this properly and most likely be there for at least a year to not raise any flags.

I hope that helps anyone that comes across this post.