First we have to define "Nazi". To my mind, this primarily means the higher ranking members of the Nazi state. However, most were dead by 1946:
Himmler (THE number one candidate) committed suicide after being captured and identified.
Goering did likewise whilst in Prison at Nuremberg.
Goebbels did likewise shortly after Hitler's suicide at the bunker in Berlin.
Boormann is generally believed to be found dead trying to escape Berlin.
Heydrich was assassinated in Czechoslovakia in 1942.
Heydrich's sucessor, Ernst Kaltenbrunner, was executed at Nuremberg.
Hans Frank (governor of occupied Poland) was executed at Nuremberg.
However, the real head honcho in Poland was Odilo Globocnik, based in Lublin. (Lublin, not Warsaw, was the Nazi central office). He was responsible for the setting up and final destruction of all the Polish ghettoes. He was captured by the British in 1945 but committed suicide.
The organisations primarily responsible for rounding up and executing Jews and other "undesirables" were the Einsatzgruppen (special action groups), of which there were at one time 8 in Poland alone, although they did operated elsewhere. These were as follows:
Einsatzgruppe I led by Bruno Strechenbach, who was captured by the Soviets, given a 25 year sentence, but released in 1955. Despite being plainly and obviously implicated by other defendants at Nuremberg, he was tried by the West German Government only in 1973 and all charges were dismissed because of his ill health. He died at home in 1977.
Einsatzgruppe II was led by Emanuel Schafer, who was sentenced after the war to 6 and a half years in prison. He boasted that because of his efforts, "Belgrade was the only great city in Europe completely free of Jews". He died at home in 1974.
Einsatzgruppe III was led by Dr.Hans Fischer. I have never been able to find out exactly what happened to him.
Einsatzgruppe IV was led by Lothar Beutel (who died in 1986) and was replaced by Josef Albert Meisinger (the Butcher of Warsaw). Meisinger was found in Japan shortly after the war and executed in Warsaw in 1947 after American authorities handed him over to the Poles.
Einsatzgruppe V was led by Ernst Damzog, who was responsible for many murders of Poles, Jews and Russians and who oversaw much that happened at Chelmno concentration camp. He was killed in 1945 in the west, during the Allied invasion.
Einsatzgruppe VI was led by Erich Naumann, who was responsible for many war crimes in the east. When asked about this at Nuremberg, he replied
considered the decree to be right because it was part of our aim of the war and, therefore, it was necessary
He was hanged in 1951 at Nuremberg.
Einsatzgruppe VII was run by Udo Von Woyrsch, who was a prisoner of the British, sentenced to 20 years, but released in 1952 and also by Otto Rasch, another mass murderer. His trial in 1947 was dropped due to alleged parkinson's disease and dementia.
Einsatzgruppe 16 was commanded by Dr. Rudolph Troger. I don't know what happened to him.
The Waffen SS often bore the brunt of Allied retribution, despite the fact that most were simply front line soldiers who had nothing to do with the camps. Too often, high rankers were let off lightly and low rankers got it instead.
As you can hopefully see from the above's small examples, the Allied effort to bring criminals to real justice was, in reality, pretty weak.
But one way or another, the main movers and shakers were all dead by 1947.