Actually have always considered Nixon a capable statesman. He opened dialogue with China, and appeared more than capable of handling Kruschev when he engaged with him during his role as VP in the kitchen debate. His administration was handed a sh!t show of a war that, to his credit, he did eventually end.
On the other hand…If I remember correctly he attempted to negotiator with the the Vietcong while LBJ was still president, which is questionable at best. Additionally, I must say that listening to the tapes from the Oval Office during his administration are at least troubling at times, and at other times make him appear as a madman. At the end of the day, had the man not been one of the most insecure and paranoid people on the face of the earth, he would be more generously viewed now than he is, IMO.