If you used the certbot you will get these files: README cert.pem chain.pem fullchain.pem privkey.pem
ssl_certificate should point to fullchain.pem
ssl_certificate_key should point to privkey.pem
ssl_trusted_certificate should point to chain.pem
From what I see, the PorkBun generated files are just renamed and mapped like this:
fullchain.pem -> domain.cert.pem
privkey.pem -> private.key.pem
chain.pem -> intermediate.cert.pem
cert.pem -> public.key.pem
So you would do this for the files given by PorkBun:
ssl_certificate should point to domain.cert.pem
ssl_certificate_key should point to private.key.pem
ssl_trusted_certificate should point to intermediate.cert.pem
Basically fullchain.pem is just made up of cert.pem + chain.pem concatenated together. See here for more information: Generate CRT & KEY ssl files from Let's Encrypt from scratch
Personally, I would not use their generated ones because you would have to manually replace it every 90 days. Best if you use another option like certbot which lets you automatically renew it or do it 'manually' via some cronjob. Good luck!