What is perceived and what is actual are two very different things, however. Part of being an Ni dominant is seeing many angles of a thing; I can't speak for others, but I can state that my ability to map my mental processes is above average. I can determine why a thought (for example) came about by retracing steps. Basic cause and effect stuff, but with a relentless internal focus and clarity.
Within the context of typology, assigning a manifest thought or action to a specific function proves to be a tad more bothersome, because you can make compelling arguments for pretty much anything. To the observer, we may seem measured and steadfast; internally, a great many things may be up for dispute.
Obviously, this varies from person to person.
As for the OP, may I recommend this channel? His information is excellent:
https://www.youtube.com/channel/UCmDcT_Pujk8vOcxk_IcnxtQ
I have been lucky enough to work alongside some awesome Type practitioners, and they also agree that his information is solid. Worth a scan at the very least.