The company's website is here [0] but I could not find any detailed information on their process there. A search term that seems to be more useful for that, even though it does not give details on their process exactly, seems to be "ammonia fixation non-equilibrium plasma"

[0] https://www.nitricity.co/

Edit: an article on the Stanford website:

https://suncat.stanford.edu/news/boots-ground-stanford-team-...

Edit2: removed name and information about research of someone who seems to be involved with the company because they were not mentioned by name on the company website and might appreciate their privacy.