I have worked with, interviewed, and sold to extremely successful people following a few simple principles. It can be scary, but preparation will help you manage the fear.
Here are my thoughts:
First, consider why you want to work for him. How will you benefit from a job with him? Don't assume that it is a good fit for you just because he is a billionaire. Are you doing it just because you need income? Or do you want mentorship? Get really clear on why this would be good for you.
Once you are convinced that this is a good fit for you, think about why it would be valuable to him. Why would working for him be a mutually beneficial situation? Are there any gaps in his business that you would be able to fill? Do you see an area that would be improved if you were working on it for him?
Once you have determined that working together would be a good situation for both of you, then ask for a phone or video chat meeting. From here, you want to have some quality questions for him that both demonstrate your expertise and help you confirm it is a good fit.
One last piece of advice: The purpose of your meeting with him is not to convince him to hire you, it is to find out if it is a good fit for both of you. This mindset will help you make a decision together instead of you being at his mercy.
If you would like extra help with the specifics, I would be happy to have a call with you. I have done this many times, and I know that it can be intimidating. Let me know if I can help in any way.