Is this yellow same as GMK Nautilus yellow?
Oohh, you thinking about pairing this with GMK Nautilus? I've been thinking about it too. Pairing the alphas of this kit with the modifiers of Nautilus (and using some of the red modifiers of Kitsune too).
I even did a mockup and it looks decent enough.
But to answer your question, it's not exactly the same. Nautilus yellow is GMK N6, and the yellow in this set is RAL 0808060. I think RAL 0808060 is a little less saturated, but judging by the render of Kistune and the pictures of GMK Nautilus these two yellows should be somewhat close.