Depends on your definition of nerd, I suppose. I think the old stereotype of the code writing, pocket protector wearing, socially inept physics major nerd has faded, but in my view that's only because many of the things which defined that archetype are now mainstream. Sci-fi/fantasy shows and movies are big deals and make millions (even if we dismiss Game of Thrones, superhero movies are raking it in along with other sci-fi premises like Planet of the Apes, and Terminator), computers and technology are mainstream and status symbols in a good way now, and we live in a world driven by scientific advancement. If the nerd has died, it's only because they've become mainstream.
If one refers instead to the idea of someone obsessed with a particular topic, well, my argument is that nearly everyone is a nerd about something, it's just certain topics (football, cars) are more socially acceptable than others (Star Trek, D&D). Most of the tropes and hallmarks of nerdiness are the same in all fields though. Books, TV shows, cosplay, encyclopedic knowledge, long conversations about minutiae, gathering with like minded obsessives. Just as true of football fans or history buffs as Trekkies.
