Interesting how you solved it, I am however looking for a ready solution, want to skip coding that web server part
It seems there is no way of running nginx on windows with asp.net, actually there seems not to be any good way of running ASP.NET apps on windows without IIS. Most other stuff is outdated

So I guess IIS is the way I will go, if I don't choose to use PHP anyway. Thanks for answering at least!