If you want people to believe your Ni, it depends a lot on what kind of person you are. If you come across as nutty and unreliable people are legitimate in being distrustful. You're essentially like that broken clock that's right twice a day.
Even if you're wrong the other 23 hrs and 58 mins (unless you're on a 24hr clock, then you're only right once
) that can be parlayed if you call attention to the times you're accurately assessed the situation. Basically, you need to get people to trust your judgment and not just demand people trust your judgment, just because you supposedly have it. People are once again legitimate in asking for proof. It's like those "Trust me, I'm a doctor" tshirts...why should I trust you?
My former ENTJ Director of IT did a lot of good restructuring while she was at my organization. People trusted her and trusted her judgment. She was basically given carte blanche in a little over one year.
She wasn't a Chicken Little proclaiming the sky is falling in the most dramatic and outlandish fashion. She wasn't disrespectful or sulked like other people where idiots who didn't
get it. Her ideas were accessible, implementable, persuasive, and reasonable.
I watched her work her magic when my department was getting a new learning management system, which was something that was supposed to be happening for four years before she took over the project. She proved to executive staff the need for more updated system and procedures. She supported her claims with examples of other organizations who successfully implemented. She researched and showed all the leaks in the current system (evidently we weren't SCORM compliant and people's credit card numbers were getting dumped in an unsecured excel table!) She told them what what could be done internally with the LMS (employee evaluations, training modules, etc.) and how we could instead of contracting out certain activities how we could move them in house in a few years (save $$$).
I think NJs often want to believe their ideas are esoteric and inscrutable but I think good Ni paired with sound Se will have people following you down any half-cocked rabbit hole you want to go down. I think it's all about presentation and supporting your claims with evidence you can scrap up. And evidence exists if you look for it usually.
Using Ni interpersonally is trickier though I think. Less evidence that you can use and it's often a matter of interpretation and perspective.
ETA: What Mr. Eyebrows said only with more words.