Nurse Overtime and Patient Safety Act of 2020 This bill requires certain providers, as a condition of Medicare participation, to limit mandatory overtime for nurses. Specifically, the bill prohibits hospitals, ambulatory surgical centers, home health agencies, rural health clinics, federally qualified health centers, and other specified providers from requiring nurses to work (1) more than a previously scheduled shift, 48 hours in a workweek, or 12 consecutive hours in a 24-hour period; or (2) during the 10 hours immediately following the 12th hour worked in a shift during a 24-hour period. Qualifying work hours include time spent in training, on call, and on standby. The bill's provisions do not apply during declared emergencies or disasters, subject to specified conditions, and do not preclude voluntary overtime. The bill also establishes (1) certain protections for nurses who file complaints against providers, (2) documentation and notice requirements for providers, and (3) potential civil penalties for violations.