yes, I've had several!
They vary tremendously.
Worst case scenario you will get grilled in some detail about EYFS: themes, commitments etc. This happened to me when we were trying to register an additional site (although this particular inspector was a dragon in oh-so-many ways ).
What is more likely is that he / she will ask you a lot of questions about the organisation of the preschool,
e.g. how do you handle admissions?
have you ever had any complaints and how have you dealt with them?
what is your working relationship like with the preschool supervisor / playleader, how are decisions made?
what are the qualification levels of your staff and what plans do you have in place to develop this?
You also may be asked a number of more 'personal' questions, e.g. about whether you have children in preschool yourself, your own career background, how involved you are with the local community, why do you want to be Chair of the preschool?
This is really to guage your commitment to the role and your overall suitability for the job.
I think it's highly unlikely you will be asked in depth stuff about EYFS, but I suggest you make sure you are familiar with key terms. Also, if you are asked a 'technical' question about EYFS which you can't answer, you shouldn't be afraid of saying that you don't know, but explain whose remit this is, and what ongoing dialogue there is between you and that person. They're basically just checking that someone understands and is accountable for all the various important elements of running the preschool.
Take the opportunity to tell him / her about all the good stuff that you do, don't wait to be asked. It's an opportunity for a constructive conversation with Ofsted (honestly!). In the course of suitable person interviews that I've had / been to, we've had a lot of good suggestions given to us which we've been able to implement ahead of our inspection. Panic not!