Diaz showcased not only his grappling prowess, but also his striking attack to get the best of Miller.
Let's take a look at what we learned from the performance.
UFC commentators Joe Rogan and Mike Goldberg have referred to Diaz's boxing as "punches in bunches" due to his high work rate.
However, in the opening round, Diaz dropped Miller with a left hand.
In doing so, Diaz proved that he has some power to go along with his volume.
Cesar Gracie doesn't hand out many black belts.
In fact, only a handful of fighters possess them, including Jake Shields and Nate's older brother Nick.
Against Miller, Diaz showed why he recently earned his, forcing Miller to submit for the first time in his career.
For much of his career, Diaz has lived in the shadow of his older brother Nick.
After all, Nick left the UFC and became the Strikeforce champion before being brought back to make a run at the welterweight title.
Now, with Nick been suspended due to a failed post-fight drug test, it is Nate who has positioned himself for a run at UFC gold.
Roughly two years ago, Diaz moved up to welterweight after dropping three out of his previous four fights at 155 pounds.
Despite winning his first two outings, he was defeated by bigger opponents Rory MacDonald and Dong Hyun Kim, leaving him at a crossroads in his career. Some even questioned whether he should continue fighting.
Now back at lightweight, he's reeled off three straight wins, each more impressive than the last.
Without a doubt, Diaz's last three wins have propelled him into the title picture.
By submitting Miller and former Pride champion Takanori Gomi, Diaz proved that he has the most lethal submission game in the division.
Couple that with the striking display that he used to defeat Donald Cerrone, and Diaz can pose problems for anyone at 155 pounds.