"Firstly, Hitler was a Christian"
No, he wasn't. He may have claimed to be a Christian, but I can claim to be an astronaut, it doesn't make me one.
Christ's own words: "Many will say to me on that day, ‘Lord, Lord, did we not prophesy in your name and in your name drive out demons and in your name perform many miracles?’ Then I will tell them plainly, ‘I never knew you. Away from me, you evildoers!" - Matthew 7:22-23.
"his regime was based on the Christians doctrines"
No, it wasn't. The apostle Peter was told by Jesus: “Return your sword to its place, for all those who take the sword will perish by the sword.” (Matthew 26:52) Jesus showed that his followers would not take up weapons of warfare.
The Encyclopedia of Religion and War states: “The earliest followers of Jesus rejected war and military service,” recognizing those practices as “incompatible with the love ethic of Jesus and the injunction to love one’s enemies.”