Just a disclaimer: I'm not qualified to give an adequate assessment about how much Bodri's work reflects Master Nan's work.
Bill Bodri's work doesn't identically reflect Master Nan's work.
According to my interpretations of their works (which should be definitely taken with a grain of salt), Bodri puts importance on correcting erroneous mental states, cultivating meditation practice, and transforming the physical body. Although Master Nan also shares these sentiments, he emphasizes them through the lens that a person must have a high degree of perception of truth (virtue, merit and wisdom) to develop lofty attainments in those areas. In his texts, he quotes Buddhist scriptures and tells his audience that they have to learn to read Buddhist texts themselves.
Bodri's approach is a bit different, especially in his later work "Nyasa Yoga". He mentions 5 spiritual bodies that a person can cultivate. When a person cultivates enough to develop one spiritual body, a person can then progressively cultivate more refined qi in this spiritual body until they develop an even more advanced spiritual body, continuing this cyclical process. Master Nan didn't mention this to my knowledge (his English translations).
In "Nyasa Yoga", I believe he mentioned that it is important that to attain the yin-shen (deva? maybe I'm mixing this up) body because once a person has that, he or she can then continue their cultivation in that energetic body and gain assistance from cultivators who have already succeeded in the process of cultivation. Even if one passes away in this physical frame, they can occupy the deva (or yin-shen?) body after death. Now, if that were true, that would be mind-blowing to me. That would mean that a person has found a solution to death and what happens after life.
^^^Master Nan hasn't mentioned anything of that sort in the English translations of his books. And he also has said that a yin body is no big deal--it's still far away from enlightenment.
There's no doubt that Bodri has expertise in this field based on his writings (well, it's not like I can definitively tell, lol). I do carry a bit of skepticism, primarily because I haven't seen any photos of him nor photos of him with Master Nan. Other than his books and his website, he remains a bit anonymous to me.