I'm looking for an alternative to try_files.
I want to check for the existence of a file and then run a redirect to other file. So according to this pattern:
if ( file_exists($my_file_on_hdd) ) {
rewrite $other_file_on_hdd;
}
Make a location block pointing to a file, and put your rewrite inside of there. It won't check if the file exists, but if you want it to redirect anyways, that shouldn't matter.