Which state presides over life insurnace law if the owner and insured are in two different states?

This is a very technical question, that would probably take some research to give you a truly definitive answer;  I suspect it's more a matter of the law of trusts and estates, rather than insurance.  Conflicts of laws -- resolving questions like this, of which state's law governs -- is a full year course in many law schools.  The answer might also depend on exactly what legal issue is being considered.

What I don't know, not being a California attorney, is whether the policy on a Nevada resident's life could be issued under California law.  If so, and the policy was issued in California, then I would strongly suspect that California law would control.