Unfortunately I have never heard of the work "nuko" but a similar word, "nuku" means to omit.
Hope that helps!
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Well basically 'nuko' equals 'neko' which means 'cats'
It's kind of Japanese word play,
In which the letter ね is changed to ぬ.
They are several explanations to the origin:
1. From typo
2. because ね and ぬ kind of look similar
3. From 'nukui' ぬくい which means 'warm' in Osaka dialect.
Because cats prefer warm places.
Nukonuko~(^-^)/
miyuki neko emi nuko akane
There are many different animes with yanderes characters. Some of the famous ones include Hikurishi, Elfen Lied, and Higurashi no Nuko. You can try these out and see if they captivate you.