My professor is rigging data and plagiarizing. What can I do?
Your backing off reaction is the appropriate one: cease any form of association with him right away.

The description of your first-hand witnessing of him fabricating data is more than enough to ascertain his academic dishonesty. You don't need to know about nanotechnology to know that manually modifying data to make it pass a statistical test is idiotic and fraudulent. Also, experts in that field will assume the data are real when conducting peer review, so it's not something they can easily detect without repeating the (alleged) experiments.

His 'results' are unwanted. By publishing bogus science he makes people lose time and money, he's robbing legitimate researchers of their funding, he is adding noise that masks the signal. If you can afford to report his behavior please, do it. Depending on where this story takes place, you might lose a variable number of feathers in his striking back, but at the end of the day he is the one who is wrong.

Taking direct action to publicly expose his fraudulent behavior is risky for you, especially since he is your hierarchical superior. But, when he will get caught (because he will), if it is apparent that you were aware of his wrongdoings and still accepted co-authorship or credit for his publications, his bad reputation is going to stain your career. If you fail to prove your claim, it's your career that will be at risk. So, proceed with caution. Note that it is ethically perfectly fine to report scientific wrongdoings anonymously.


Make sure that all institutional reporting routes are inefficient before bringing the issue to another level. It is not clear in your post if you actually tried or if you just assume 'they won't listen to you'.
Since you provided the content of at least one paper, and know about its fake nature, if he submits the paper despite your protests, notifying the editor is a thing you could do. Editors will take you very seriously in reputable journals.
You can also take part (anonymously if relevant) in a post-publication comment on his papers, on websites like pubpeer.com or retractionwatch.com.