Can an employer terminate an employee for violating a company policy that is neither in writing nor communicated to the employee

With the exception of employees governed under labor agreements or express contracts, in Nevada as an at-will employment state, Employers can terminate an employee for almost any reason or for no reason at all, so long as it is not a prohibited reason.  "Since employees in Nevada are presumed to be at-will, an employer can dismiss an at-will employee with or without cause, so long as the dismissal does not offend this state's public policy. (citations omitted).  public po policy. While [Nevada] has recognized certain exceptions to the at-will employment doctrine (citation omitted), these exceptions are 'severely limited to those rare and exceptional cases where the employer's conduct violates strong and compelling public policy.'" Ozawa v. Vision Airlines, 125 Nev. 556, 561 (2009).