A few different outlets are reporting on this newspaper column piece from January 4, 1934 in the Green Bay Press-Gazette. This article is from an older, more orange-hued time in Hitler’s life—1920s, when young Adolf fresh out of prison was considered by polite society to be something of a joke. Germany was in a bad way after World War I and their war debt to the winning nations was a severe point of contention.
Adolf Hitler, out of prison, took advantage of the groans. He told people that he would make Germany “great” again. He blamed Jews, Socialists, Communists, and others for the troubles of the land. His blazing speeches gained followers for his “cause.”
According to Gizmodo, the “great again” phraseology appears again in 1940 in a Missouri article.
“Nationalism and Socialism had to be redefined and they had to be blended into one strong new idea to carry new strength which would make Germany great again.”
Even more frustrating is that Snopes, up until this news hit yesterday, had the claim that Hitler had used this kind of similar phrasing as “mostly false.” Today they have it as “a mixture.” They are sticking to the idea that Hitler didn’t use the phrase as a slogan. Also, here’s the conclusion on the Snopes page for irony’s sake.
While an underlying theme of Nazi propaganda may have been "making Germany great again," a message that directly contributed to Hitler's rise to power, this does not mean that Donald Trump (or Ronald Reagan, or Margaret Thatcher, or Ferdinand Marcos, or anybody else) necessarily campaigned on Nazi principles.
But, it kinda does.