The Great Dictator is a great movie. It gives me satisfaction to know that Hitler watched it and thus had to endure being mocked. Chaplin’s Hitler-like character in the movie did a funny speech - it was in a mixture of a kind of mangled English and German. Instead of the swastika, the symbol was a “double cross.” For those who have not seen the movie, Chaplin played two characters. One was a bumbling Hitler-like character and the other was a Jew who discovered that his country had been transformed into something awful.
There is no evidence that Hitler had watched it or even had it, all his films were screened for him by staff and since it came out in 1940 after the start of WWII in Europe it would have been difficult to get it into Germany
People like Hitler are so used to being ridiculed they honestly don’t care.