Ok, I should be asleep but will take a stab at this. My Ni is my subconsious, they are one and the same. I am very in touch with that part of my mind, at least compared to most. I spend a lot of time there even when I'm awake. It doesn't need to be feed all that much. It shifts though all the trivial BS and always finds the crux of any situation or problem. Often, the details are flowing by unnoticed until that one important thing comes up then Bingo! It doesn't always come up immediately. Sometimes the eureka moment comes later after I sleep. I know for a fact that I am still processing when I sleep. I can even give my subconscious mind "homework" sometimes, and get the answer later on.
That's how it works, but it's really hard to explain why it works. Or why it doesn't work like that for non-Ni users. Some people crave the stimuli, even if it's not needed for understanding. It just bogs me down. I once heard Chess explained as "seeing the heart of the position". To me this means not getting sidetracked with non-essential details (which most details are). Ni allows you to see the heart of the position.
So is this why INTJs are usually so good at chess?
I wonder if my mom and dad are Ni-doms. I haven't figured their types out yet completely but my dad is really good at chess (all I know for sure is that he's a J... he just doesn't seem "mystic" enough to be an INFJ and not "arrogant" enough to be an INTJ) and my mom says that she doesn't really dream at night, she *processes information*. She's also very intuitive. Often she's had the feeling that something is going to happen and then it happens, things that most people wouldn't guess are coming.
For myself, I can think of times when I have "just known" something, but I don't know if it happens often. Like, when I visited an online acquaintance of mine for the first or second time and urged him to pick one of my paintings-- I didn't know anything about his artistic preferences-- I had a feeling that he was going to pick the gloomy, abstract painting. He just seemed to be the kind of personality that would like that kind of stuff. And he picked it. I don't know if that intuition was Ni or some other function working.
When I was a child, I sometimes tried to attune my inner clock to wake me up at a certain hour in the morning. I just went to bed, thinking, "I'll wake up at six o'clock". My mom told me about the technique, and usually it worked.
I haven't done it in a long time, though.
My dreams have usually been quite imaginative, like, normal dreams, instead of "processing information". Sometimes, though, I don't dream but process information. Mostly it happens when I've been reading for an exam. Then my mind is so cluttered with new information that I've got to sort it out in some way.
I like chess but am pretty average at it.
Does that mean that I don't have stron Ni?