Nev. Rev. Stat. § 293.520
Except as otherwise provided in this section, the preregistration of persons or the registration or reregistration of electors who are unable to sign their names must be made upon personal application of those persons or electors at the office of the county clerk where they may be identified or in the presence of a field registrar. If such a person or an elector is unable to appear in person at the office of the county clerk, the county clerk shall send a field registrar or an employee of the office of the county clerk to the elector to identify the person or elector and preregister the person or register or reregister the elector, as appropriate. The persons or electors described in this section may use a mark or cross in place of a signature.
NRS 293.520