Supposedly NGINX gives you better peak performance and the configuration file format is more popular.
I would guess that peak performance is only a concern when being google/netflix/amazon, otherwise I would bet the bottleneck is somewhere else.
Further, NGINX seems to have become the default reverse proxy for all start ups, companies etc. around 10 years ago and thanks to group thinking by now one has to explain when using something else than NGINX.
What I really miss from Apache is Apaches awesome letsencrypt module w/o the need for certbot. (If somebody knows about a module for NGINX which takes care of letsencrypt w/o certbot, please enlighten me.)
In summary: Technical Apache and NGINX are IMHO mostly interchangeable (outside of peek performance demands), but the market/herd/group think prefers NGINX.