m8, you're being way more secretive than there's need for.
Most (pretty much all) of the nexus keys are story related, so Chastity will give them to you (check the leads if you forgot)
Usually you just need to type the text that stands out (colored orange probably)
There is a few secret ones, but I'll tell you the one that's actually useful in a slightly secretive way.
You to the nexus and think about someone that lives in the mountains, someone mysterious, someone who only helps you as much as necessary, no more, no less.
Also not sure if calling for help while in the nexus would do anything.