This was the most current question I could find regarding this topic. I haven't sent anyone a friend request nor have I received any. Yet, someone did add me to their friends list and, somehow, in my Nexus Mods profile, it states that I added them as a friend and they appear in my Forums profile friends list. So, it seems that some sort of "automatic approval" is happening. Is this coming from the Nexus Mods profile "Add Friend " button (which is inn the same place you can "Track Author")?
If I don't want this member as a friend, it seems my only recourse is to click on the friends button in my Nexus Mods profile and "Remove Friend".
I don't see a way in the "Edit your site preferences" to change this.
So, the bottom line seems to be that anyone can add themselves to your friends list and if you don't want them, then you have to remove them?