For Petes sake, I said I don't care what YOU think.
No, and that is my point. There is only one truth. Bigfoot exists as a real animal, or it does not. No single subjective experience is going to change that objective fact. Nathan said "the truth". I take that to be different than "his own personal truth". That is as far as we (you and I) overlap in your statement. When someone says the truth, I take the wider, objective meaning of the word, not the more narrow subjective approach where the truth basically means whatever that one person perceives it to be.
Nathans truth could very well be wrong. This would be a surprise to him, but that does not matter to the objective fact that his sighting could be a fabrication or a delusion of the mind. His truth could be different than the objective truth. People seeking the truth should not aim to align that with someone else's experience, but should aim for the objective, demonstrable truth instead.