Ne picks up on patterns, expands on them, and comes up with a multitude of ideas based upon one thing. It may see multiple potential outcomes to a given scenario and it's a matter of narrowing it down to the most likely outcome. Ni is about one idea, focus on one thing, very future oriented take multiple bits of information and condensing it into one though. Ne first can be very rapidfire with it's associations while ne second or developed tertiary ne may take a little longer.
On the other hand, ne is more coming up with a bunch of different concepts and ideas based on one thing.
Ni and ne are both about association, connecting ideas in an abstract sort of way, but ne is more expansive and scattered. Ne is also about association, seemingly jumping from one idea to another. To a ne-user, there is a rhyme and reason how those things are connected and it can be explained. To an outsider, it may seem completely random without getting from point A to point B being explained.