Why didn't he give himself up and in Nuremberg trails could of told all the white nations that they are making a big mistake.

You've just described Herman Goering, who was the second highest ranking Nazi that offered to surrender but was still killed at the trials.

https://en.wikipedia.org/wiki/Hermann_G%C3%B6ring#Trial_and_death

And ironically, there was another High level German who was captured by Jews and killed by them. Adolf Eichmann.

https://en.wikipedia.org/wiki/Eichmann_trial

Hitler clearly knew surrender was pointless given the fate of Mussolini, whose executed body was paraded in the streets.