How to correctly add a new user to a group via Dockerfile?

Question

Docker

Hello, I need to add a new user

www-data

and add it to the group

nobody

i wrote something similar

RUN adduser -S www-data -G nobody

USER www-data

But when it comes to the command

RUN chown -R nobody.nobody /var/www/html

, it writes to me that I do not have enough rights, how can I fix it?

PS I collect on the Alpine version