This is not the only time someone has suggested the connection, but in my mind there are several holes in the idea, even some that weren't mentioned by the previous post which does quite a good job.
Hitler couched much of his policy and his ideals in a very "righteous" way, the idea that they would be returning to the morals and righteousness of a forgotten time in Germany. He obviously used the depredations of the Treaty of Versailles and the failed state-like conditions that it induced in Germany, but he also appealed to a sense of order and a sense of a higher power, something that Jack is clearly (at least in my mind) pushing back against as he appeals to the boys baser instincts.
The connection, I think, is one that people draw because of the idea of blood lust and the desire to kill and to maim and though Hitler certainly pushed the Army and the SS and many others to do horrible things, he rarely used that so blatantly as his appeal to the people, whereas Jack says simply that they are strong and can kill and satisfy themselves and that they needn't be afraid.
Yes he does in many ways. He lead his hunters into savage, cruel situations much like Hitler did with the Nazi soldiers. He becomes almost like a dictator over the group of boys killing those who stood against him. When we are first presented to Jack he is to bring hope and salvation by hunting and being civil yet he fails to do so and not only that but he actually leads them away from good and into evil.
Oh gosh, no. First of all, he's a boy playing at hunting, not the ruler of a real nation with real people and serious political issues. Jack is a character, designed, not real; his choices are controlled by an author, he has no actual power to do anything dangerous in real life--he's not trying to exterminate Jews or rebelling against the Versaille treaty; he's not eloquent at all, nor do his followers follow him out of almost mystical awe; he does not even create the illusion of a beautiful new order--he's all about parading his ugliness. He hates laws and order--though Hitler was above the law, he knew the significant power of documented rules and of written definitions. And Hitler's anti-intellectualism was not tribal; it was collegiate; it masked itself in the guise of super scientific education, and in fact, in "The Night of Long Knives" Hitler had savage brutes like Jack, the SA Brownshirts, killed--he would not value Jack's painted face or disrespect for duty; he would find Jack's whining and grinning and excuse-making and cape-wearing repulsively feminine.
So that's enough I think--hope I helped you,