NICER observation list: Target ID 768201

4FGL J1943.9+2841 is an unidentified Fermi-LAT source with a pulsar-like GeV spectrum. X-ray observations with Swift identified a bright X-ray source near the center of the 4FGL positional uncertainty ellipse. An optical counterpart, showing strong H emission lines, is coincident with the X-ray source. The optical colors, X-ray + optical spectra, and the GeV emission make it a strong redback millisecond pulsar binary candidate. Interestingly, the source has also shown a decrease in X-ray flux by a factor of ~20. Such changes in the flux are often seen in the rare subclass of redback binaries known as transitional millisecond pulsars. Here we propose a NICER TOO to observe this source the next time it enters and X-ray bright state to search for X-ray pulsations and orbital modulation.