Re-open divorce?

I am currently awaiting the Franchise Tax Boards assessment of non reported
"embezzeled" monies that my ex-wife stole. I was not incriminated in the
criminal phase and because we filed jointly, I am being held liable. I was
denied Innocent Spouse Relief (poor litigation from the firm I'm working
with). I'm 2 years divorced (completed myself) and my question is, Can I
reopen my divorce to add that my ex-wife is fully liable for the embezzeled
funds?

You can sue her for any liability you accrue. She will lose without question and be liable to you.

You cannot easily re-open the divorce but if you argue she fraudulently withheld info, it may be allowed.