Unfortunately, under the Nevada Motor Vehicle Drivers' License Act Section 483.250, the state cannot issue a license to a tourist or any other person who is not an actual resident in Nevada.
483.141. "Resident" defined.
1. "Resident" includes, but is not limited to, a person:
(a) Whose legal residence is in the State of Nevada.
(b) Who engages in intrastate business and operates in such a business any motor vehicle, trailer or semitrailer, or any person maintaining such vehicles in this state, as the home state of such vehicles.
(c) Who physically resides in this state and engages in a trade, profession, occupation or accepts gainful employment in this state.
(d) Who declares that he or she is a resident of this State to obtain privileges not ordinarily extended to nonresidents of this State.
2. The term does not include a person who is an actual tourist, an out-of-state student, a foreign exchange student, a border state employee
or a seasonal resident.
Being that your nephew is only going to be there for a few months, he does not qualify as a resident and cannot be licensed.