in terms of stand up, i believe silva is better than diaz in that he hits harder, is faster, and can avoid getting hit better.
Even on the ground silva should be able to defend anything nick may try if it even gets to the ground.
Basically for silva to beat diaz is no big deal to me, this fight is all about money...however if diaz wins it will be huge for his legacy.
If nick puts his hands down and taunts silva could easily start tagging him, wouldn't be surprised with a front upkick to the face, silva can finish with hands or kicks so keeping distance will be key. also if diaz comes charging in with flurries he risks getting muay tai knees to the face like silva did to franklin.
i think silva wins relatively easy, but can't count nick out either if he lands volume punches and wobbles silva, nicks the type that would go for the kill and finish its mma anything can happen, but on paper i see this an easy win for silva.