With over a decade's worth of experience in web development and configuring servers exactly like Nginx, I am absolutely confident in my ability to seamlessly solve your file upload issue. I've already managed countless situations where errors similar to your 413 Request Entity Too Large arose, often times dealing with substantial file sizes crossing predefined thresholds.
In addition to this, I am well-versed in multiple programming languages including PHP which is relevant to this project. My advanced knowledge of Nginx means that not only will I fix the current problem you are facing, but also create a configuration that ensures seamless and efficient file uploading on your server going forward. Whether it's modifying the client_max_body_size or adjusting other relevant directives for maximum performance, I'll do it with ease.
Your time and budget are incredibly valuable, which is why hiring someone who can get the job done quickly, correctly and efficiently is crucial.