Are there herbal supplements that can treat a mrsa lung infection?

No: This is a potentially life threatening infection that requires treatment with specific antibiotics that will treat the specific mrsa, and requires close medical supervision.

No: I am not aware of anything that is really effective against MRSA except commercial disinfectants and good hygiene and using a wound ointment called mupirocin.

And of course for lung infections you would have to use IV vancomycin or another such antibiotic to actually treat such an infection.