Beneficiary, IRS & Taxes

My wife is the beneficiary of my retirement funds.

(NOT talking about SS, but CALPERS)

She currently has a ITIN just for tax purposes, but assume she will lose her eligibility for this once I pass.


Question is this, Her being a non US citizen and never having lived there, will she be required to file a tax return with IRS from here and pay taxes on the monthly benefit funds or can she go exempt and receive 100% of the monthly beneficiary amount ?


Seems there should be a easy answer to this but for the life of me I can't seem to figure it out. I know there are a lot of educated intelligent people here, so maybe someone has some input, advise or guidance to share with me...