Great news. He seems like the total package for what you want in a recuit/commit. Smart kid, local (if that's important), size, athleticism, upside, skill.
I would bet DE. Just because that's what everyone's been saying. I can't see him on the O line because although he's huge, he still looks somewhat lean. His arms and legs don't look like an O lineman. He looks more like a basketball forward. I know he's young and he'll have weight room time, but no matter what happens to his development, his body type doesn't remind me of an o lineman.
I'm not saying he couldn't potentially becomes 6'7'' 300, but he looks lean.
Also, I think he's an exciting prospect because of his versatility and size. But, at DE his height worries me. Don't get me wrong, the thought of a 6'8'' 280 lbs athletic freak DE is awesome! But if you look at guys that are somewhat like that: Julius Peppers, Jason Taylor, JJ Watt... those guys are pretty much the best DEs. The 6'6'' or even taller than that guys. But the thing is about those players, they are all world class athletes. Incredible explosiveness, speed, just supreme athletes all around. Some of the most impressive physical specimens the NFL has seen ever.
My point is, to be a great DE at 6'8'', Nelson will have to be an extremely good (freak) athlete. That position requires an incredible amount of leverage, and the expression "low man wins" is famous for a reason. I haven't really seen any Nelson film so I wouldn't know. But being that tall can be hard for lineman.
I know you're thinking that I'm crazy and if anything, the bigger the better. But sometimes I think a 6'3'' or 6'4'' college DE is perfectly sized.
Now, being that tall and long also will benefit in many ways, including different aspects of leverage, no matter what position he plays.