You should add the license into metadata for the asset packs:
"Edit asset pack->Metadata->Release Info->License for assets" It will increase the size of audience that will be able to find your art
Viewing post in Base Character Sprite (Humanoid) comments
If you think that it was useful for you, you can leave a comment here to support my proposal about making metadata more visible for those who are interested in it https://itch.io/t/2919128/metadata-encouragement#post-7952450
I have one question about license. Why it is CC-BY-ND? WHat is the sense? ND means that user can't create derivatives but it is a base of character that assumes modifications to it... Or you expect that someone will use it as is? But you said in description you can recolor that itself a derivative...