This is tough. Let's see....
After the invasion of Poland, French troops make a foray into Germany and meet surprisingly little resistance. A strange elation overcomes the Anglo-French high command and they advance into the Reich. It is after five days of smooth running that they meet determined resistance from troops rushed from the investment of Warsaw - which allows the Polish forces to cling on to their beleaguered capital. Germany now faces a two-front battle and the invasion of the Soviet armies into Eastern Poland, while removing some pressure, does not give them the breathing room they hoped for. Materiel and resources begin to tell. By late 1940, the Wehrmacht collapses, hollowed out by irreplaceable losses and a steady pounding of its supply lines by British strategic bombing. Hitler commits suicide. Much of the remaining Nazi leadership go into Exile in Argentina. The only war crimes trials are small-scale, officers overseeing atrocities in Poland.
Germany is de-Nazified and returned to the democratic, capitalist fold with a vengeance. A French vengeance. Reparation payments and territorial losses to compensate Poland are imposed and Anglo-French troops stationed at various key points to prevent a 'return of the Nazis'.
In this TL, collusion with Stalin and aggression in Eastern Europe are seen as the greatest crime of Hitler. His Nazi movement is portrayed as Communist stooges of the vilest kind. Germany soon finds itself re-armed as a member of the anticommunist Anglo-French European Defense League, with its elected government carefully vetted not to stray from received wisdom and its industry bearing much of the cost of arming the alliance containing Stalin. There is no payment for this, it's part of the reparation scheme.
By the 1960s, many Germans are disillusioned with the democratic regime that pits them against a Communist enemy they often have secret sympathies for and siphons a large part of their industrial surplus into arming corrupt East European regimes they have no liking for whatsoever. Many young people turn to a romanticised vision of all that was good about Nazism and authoritarian regimes, idolising the doddering Mussolini and Franco as what Hitler would have become - a benevolent leader of a strong and united people (well, that's how they see it).
The Nazi counterculture mostly consists of groups of people meeting in the forests, camping, worshipping nature, practising strange, vaguely neopagan rites and free love, venerating 'Ancient Aryan Wisdom', keeping themselves fit, extolling community spirit and discipline and reviling egotism, pacifism and capitalism. Some of them become terrorists, but most practise their beliefs at hobby level, hoping one day to go back to the land and join a nazi land commune (they call it a 'Volkshof')
Many young white Brits, French, and Americans are disillusioned with the perceived money-grubbing, conformism, Christian dominance, and corruption of their nations. They long for a clean, wise, enlightened, emotionally satisfying and mutually supportive society, and the strange but alluring 'Völkische' communes are the ticket. They present themselves as the middle way - lacking the iconoclastic brutality of Communism, but renouncing the stifling conventionality of western capitalism. By 1970, a number of ethnic communes have been founded in the US and student organisations all over campuses preach the gospel of communion with nature, solidarity with your blood, and becoming a superior human. Naturally, the desegregation causehas less pull among them, but most favour black nationalism (it looks like a natural solution to them). When the environmentalist movement ties into the 'blood and soil' ideology, calling on the government to preserve the people's heritage for untold future generations rather than exploit it for short-term gains, this new breed of 'Compassionate Fascism' has arrived in the mainstream.
Of course it's not exactly Nazi, but it comes close to what surprisingly many people at the time thought Nazism was about.