Something that can keep count of average characters from RAWs or translated chapters as some readers tend to avoid novels that don't have as many chapters translated, although some novels have many more words than the average novel.
Impossible for this data to be obtained in a reliable manner, NU doesn't host novels, only links them, so it has no access to the word count of each of them. It would be necessary for it to be added manually by the users and/or translators, considering how many trolls are around and that the amount of translators that actually use NU is minimal... It's probably never going to happen.
Like what Brasca-chan said, I don't think this is possible. You'll probably just have to make do with checking out at a random chapter's length and imagining that the other chapters have the same word count too. Most novels I'm reading so far don't have a large word count disparity in each chapter, plus many translators put up notes in advance about whether a chapter's short length is the norm or not.
Even if it was possible(which it is using services such as this link) it would run into the problem of so many sites getting the page that links to the actual story chapter rather than directly linking to the story itself thus giving wrong readings. Also I can't find one that actively has an api so doing it would just be annoying since you would need to write in each url for each chapter then average them. *dies*
It might be hard for an average character count, but how about something that's not as detailed, for example having chapter length: short, medium, long and each of those containing a range e.g. 4k-6k can be considered short/medium/long?