People still unaware of how good thomson is, he has a good chance of winning this. His best assets will be speed, scrappy/technical and takedowns, and he is quite capable of all against diaz.
Diaz doesn't want to be plodding around like the benson match which really handicapped him like it does every fight his brother has. If nate keeps pressure and actually starts cutting angles like he should have been trying last fight then he might stop some of the takedown threat and cut in with some reach. Also diaz needs to lay his whole fight on to apply his full cardio which might be an advantage.
Overall I think thomson takes this, and I think he is one of the best in the weight class as well. He is more rounded than most, with some extra scrappiness still a part of his style which makes him so dangerous. He beat melendez last fight too. When he is on he is hard for anyone in the division.