How to copy HTML files to include into nginx?
The docker build command builds Docker images from a Dockerfile and a “context”. A build’s context is the set of files located in the specified PATH or URL. The build process can refer to any of the files in the context. For example, your build can use a COPY instruction to reference a file in the context.
From docker build documentation.
As you run the docker build with the . path for the context, it will try to find the folder home/nicholas/html from the context root@mordor:/home/nicholas/docker/nginx
The COPY command documentation shows some examples