An interesting match up. I think that Nogueira is probably the most dangerous (besides the fact that he is the best HW in the division IMO) fight for Lesnar. Very good boxing. Frank was getting through to Lesnar and if it wasn't for a flying knee, who knows how the fight could have went. Nogueira has the advantage standing and if it hits the mat, Nogueira has amazing submission skills (obviously).
Of course, the Nogueira/Brock fight could go similar to say Nogueira/Barnett (I or II), but I see it more going the way of Nogueira/Coleman to be honest.