It sounds like you may just want to use [name]Nico[/name]/[name]Niko[/name], though, and in that case, [name]Niko[/name] seems more “complete” as a full name to me for some reason. (But I would rather see it used as a nickname myself. [name]Nicholas[/name] and [name]Dominic[/name] are two of my favorite names!)
[name]Nico[/name], followed by [name]Niko[/name]. The 'e’s in it just look off to me. And I think [name]Nico[/name] is pretty uncommon in either pronunciation in English speaking countries so people will go with what you tell them to.
Thanks everyone. “[name]Nico[/name]” is also my preference and now I have backup I also wasn’t aware of the “cat in Japanese” connection for the spelling “[name]Neko[/name]”