Nulling is not my area, but this is a plugin connected to their site, running on their API, which goes on to being translated by Google and delivered by their cloud.
I don't think it's possible to use this plugin without paying for it.
The good news being that TranslatePress is there nulled and working.
Since they ask you to provide your own Google API for translation and then that translation is stored on your database, it's possible to run it without paying for it.
Either you create a Google Cloud account to get the free credits they offer or you use DeepL for translation (it's better), which is free until 500.000 characters, and you can create unlimited free accounts on it to get more characters (you don't even need a new email for each one, just a new VCC).
Hope it helps.