Personally, I don't find the DNCH system helpful when it comes to individual people.
As in, it is rather focused on differentiating group role behaviour.
I also don't think it makes sense to type yourself as a subtype that is not even part of your valued functions.
Ne subtype of ILI is not too bad, but could you imagine an IEI being "Te subtype"? That makes no sense.
That's why I'd prefer it if people were like "I relate to Creative subtype" without putting the Ne label behind it.
Because functionally, it does not make sense for an Ni lead to be Ne subtype.
Technically, the Ni subtype of ILI also has boosted Ne, so I guess that is where identification comes from.
In your particular case, it is likely related to you having stronger E4 tendencies.
And Type 4s almost always see themselves as being "creative" in one way or another.
All in all, I don't believe people can be the subtype of any IE, but rather only of the first or second function, and this determines which other functions will be "boosted".