I'm a little confused by your answer. Do you have an MFA in nonfiction or have you gone through the application process? Obviously, I know you want to show your best work, but that still leaves me with choices.
I'm sorry to have confused you.
I don't have an MFA as I'm in the UK, where we have MAs instead.
My MA is in writing, and I studied mostly writing novels and short fiction. I graduated with a distinction, and got one of the highest marks the University had given at that point. I was asked to teach the course afterwards but declined for personal reasons. But I worked as a non fiction editor for most of the Big Six for quite a while, and a few other publishers too, which might help make my comments pertinent.
To clarify my earlier comment, you can spend all the time you like working out what the University might like best, but you're not taking the MFA course to please the University: you're taking it to learn stuff which will interest and assist you. For that to happen you have to be accepted because the work that you want to do matches the work the University wants to see. So send in samples of your work which most pleases you; work which is closest in tone and style and subject matter to the area in which you want to work. Don't send in samples which match what you think the University wants to see. It might make you more likely to be accepted: but it won't necessarily get you what you want out of that very expensive course.