Yes, you can usually submit an expired NCL OBC certificate during form filling if the portal allows document updates later or if it's clearly mentioned that you can provide the valid certificate during verification. Many institutions understand that getting a new certificate takes time, so they allow provisional submission with a note that the updated certificate will be submitted before the final verification. Just make sure to apply for the new certificate as soon as possible and keep proof of application handy, in case you're asked for it.