The meaning of NHI depends on the context in which it is used. Here are some possible meanings based on the search results:

• National Holistic Institute
• National Health Index (New Zealand)
• Nuclear Hydrogen Initiative
• No Human Involved, a slang term used in law enforcement to describe crimes committed against people deemed undesirable or subhuman, such as those with criminal records, sex workers, drug addicts, transients, or people of color
• National Health Insurance, a specific national scheme

It is important to note that the slang term "No Human Involved" is considered offensive and dehumanizing.