Of course not. The words "Nazi" and "Hitler" have been abused these days that they have lost meaningful use cases. Simply raising the "Greater Tibet" concept doesn't make him a Nazi or Hitler.
That being said, I still feel it ironic that Dalai Lama clinches to the "Historical Tibet Areas" concept which mirrors exactly the territory claim over Tibet by Chinese government. So maybe Chinese government and Dalai Lama are actually BBFs.