Depends on to what "nag screen" you are referring? Details pls. Or a screen shot.
Look around the web. There are 'recipes' for downgrading. Personally, I have no interest - I rather like iOS 10 and it has not harmed the performance of my iPod Mini 2 o iPhone 5 in any way.
"not all those who wander are lost….." j.r.r. tolkien
Last edited by rgray; Oct 5th, 2016 at 12:07 AM.