This is the problem with passing posts 3 months after.
Now I have absolutely no clue of where this word came from, where I read it or heard it, or how I got it meaning. It does not come in dictionaries or in the internet, which is weird, however I somehow got to know its meaning. What I had noted is:
“Nickaboo“(p)= foolish stupid person.
I’m guessing the ‘p’ refers to ‘person’, although I’m not sure. I don´t know if the word is an adjective or a noun neither, and if it’s some kind of dialect word.
Nevertheless, since I noted it down, it’s clear I came across it somehow, thus, it must exist in some context. So here I leave it, for other people who may find it.