Ninja forms Unique ID

I was searching for the same … anyone having an idea or a custom-field script that works?

https://docs.ninjaforms.com/customer/en/portal/articles/2121401-emails-and-actions#shortcodes

[nf_sub_seq_num]

This will replace the shortcode with the sequential ID number of the submission.

Example:

Hello, User! Your reference number for this submission is [nf_sub_seq_num].
Displays:
Hello, User! Your reference number for this submission is 174 .