Nissan’s board of directors is set to meet on Monday as the company’s top executive, Hiroto Saikawa, faces a widening crisis of confidence in his leadership.

The board is expected to hear the results of a 10-month investigation into the company that was prompted by the arrest last November of Carlos Ghosn, its former chairman, who has since been charged with underreporting his compensation as well as other financial impropriety, allegations that he denies.

Mr. Ghosn’s fall left the company in chaos. In the months since, its profits have dropped precipitously, its alliance with the French automaker Renault has frayed, and its leader, Mr. Saikawa, has been engulfed in scandal.

Since Mr. Ghosn’s arrest, Nissan’s internal investigation has grown to encompass many other aspects of the company’s affairs, including the compensation of Mr. Saikawa and other top executives.