you'll need to compile nginx with rtmp module, which has not been in development for quite some time but it a) still works great b) still is the mode supported on services as twitch. SRT is set to take over, and i think some have done their own compile of obs and third party srt , but i havent seen any nginx compatible "module" equivalent to that of the rtmp module for nginx, *yet*.
An alternative is also to setup a VM, instead of a separate physical pc, that hosts as incoming for obs that ships streams out over rtmp to various services. It seems to work great for some, albeit at a latency and overhead cost of running the vm and the latency penalty to the os. But if input lag and such isnt a concern, i'd go that route.
