What would be the best way to find foreign professors for a PhD defense panel? I need some researchers to review my PhD thesis. I am from India and my university is also in India; the research data was collected in India. My university rules say my thesis should be reviewed by experts from the same field and another country before submitting it.

Question: What would be the best way to find specialists in a specific field to participate in a PhD evaluation panel or as reviewers? Should I just leave it to my supervisor?
Given that you've written a thesis on the topic, you should know who the experts are.  They are the authors of the papers you read and cited.  Hopefully you have also met them at conferences.  Of course, your advisor should also know these people.