Dave Melzter is reporting it's true: Antonio "Rodrigo" Nogueira is coming to the UFC. Apparently he was even at the UFC Fight Night event, but was never introduced (Melzter thinks the UFC should've said something about it, but that makes the formal debut all the more mediocre).
What's interesting about this is Dave usually gets these predictions right. Whatever inside source he has is giving him good info. But Jordan Breen, formerly of Complete Vale Tudo Access and now with Sherdog, has stated Nogueira is 80% blind in one eye and would never be allowed to fight by any athletic commission. In fairness, Breen never "officially" made the statement in a formally written piece. But he seemed convince and told others. That's enough to count.
Surely if this were true the UFC would know by now. Breen does excellent reporting on the Japanese MMA scene and usually has good sources, but for my money, I'm going with Melzter.
As for Nogueira, there isn't anyone in the UFC who can stop him if he's healthy save maybe CroCop. He has the best guard of any heavyweight in the world, excellent boxing, a granite chin, good cardio, and sharp wrestling technique. A match-up with Arlovski or Sylvia is something we'd have to see.