Kyrgios has heaps of talent. Even more importantly in my eyes, he has that certain flamboyance and arrogance to him that I feel a great champion absolutely must have. He considers himself every bit the equal of the big three, and in their H2H matches at least, has backed it up.
However, when talent is extremely raw, it can seem greater than it actually is. Kyrgios' technique is severely lacking in several areas, especially on accelerating the ball out of uncomfortable zones ( which is why he pretty much junkballs 90% of the time in baseline rallies), and the ROS. With these deficiencies, he gets by purely on shot making talent, which might make him seem more flamboyant/talented than a Nadal whose fundamentals are forged in steel. Once he clarifies his technique and refines his game further (as I really, really hope he will) he will seem less mercurial and talented but be a much better player.
I think right at this point it is very difficult to compare the talent of a Kyrgios with that of a Nadal/Djokovic.