Translation:Now, the chief has his back against the wall.
That is literally what "to have your back against the wall" means in English. "To" or "against" are both correct. https://dictionary.cambridge.org/dictionary/english/have-your-back-to-against-the-wall
To have your "back up against the wall" is to be in a bind, like in this U2 song: https://www.google.com/search?q=sunday+bloody+sunday&rlz=1CAASUB_enUS640US640&oq=sunday+bloody+sunday&aqs=chrome..69i57.2689j0j7&sourceid=chrome&ie=UTF-8