I work for a Mortgage company that has a corporate locations in Oregon, West Virginia, and its Headquarters in California but has retail/satellite offices in nearly all the continental US. I'm moving to lower cost of living and be closer to family members that need additional support and just purchased my house in Nevada (closed 2021). I know I have to pay CA income tax for 2020 but how should I be filing for 2021?
Once you become a resident of NV, as a W-2 employee you can only be taxed by CA on CA-source income. CA-source income is income from work actually (physically) performed inside CA. It also includes income earned by a sole proprietor/independent contractor for services provided to clients located in CA, regardless of the sole proprietor's location. Sole proprietor compensation is reported on a 1099-NEC or a 1099-MISC rather than a W-2.
NV has no state income tax.
You become a resident of NV when you begin living in your new permanent home (your domicile) in NV.