@satya-pat
(If you are a US citizen or green card holder, you pay US tax on all your worldwide income no matter where you are living according to all the usual rules. It seems from your question that you might not be a US citizen.)
If you are not a US citizen or green card holder, and you live overseas in 2022 (less than 182 days in the US) you are a non-resident alien and you file a form 1040-NR. You only pay US income tax on US-sourced income. Likewise, as a CA non-resident, you pay CA income tax on your CA-source income.
Your RSUs are US source income to the extent you worked in the US between the granting and vesting dates. For example, suppose the RSUs were granted July 1, 2019, and you continue to work for the employer, you leave the US on 12/31/21, and you sell the RSUs on 6/30/2022. Since you lived and worked 5/6th of the vesting time in the US, 5/6th of any income will be considered US-source and be subject to US tax on a 2022 form 1040-NR.
https://www.jdsupra.com/legalnews/globally-not-so-mobile-employees-17014/
The stockbroker may be required to withhold up to 30% of any sales proceeds, if you are a non-resident alien. You would get credit for this withholding on your tax return which would probably generate a tax refund. You will want to check with the stockbroker before you make the sale.
