I’ve never seriously encountered that question. Then the Supreme Court of Nevada decided McGowen v. Dist. Ct. The question was whether the plaintiff’s attorney or legal staff could serve a summons and complaint upon a defendant. At the time, NRCP 4(c) stated “[p]rocess shall be served … by any person who is not a party and who is over 18 years of age.” McGowen concluded that language was unambiguous and read it literally. The attorney and legal staff were not parties to the case and were more than 18, so service was appropriate.
Serving a complaint under Rule 4 is different from serving a subpoena under Rule 45. But NRCP 45(b)(1) states “[a]ny person who is at least 18 years old and not a party may serve a subpoena, as appropriate under Rule 4.2 or 4.3.” This is effectively the same language as NRCP 4(c) once used and my bet is an appellate court would interpret it the same way.
There are many other, far more cost effective ways to serve
a subpoena rather than having counsel do it.
However, if all else fails, it might be acceptable service.
 134 Nev. Adv. Op. 89, 432 P.3d 220 (2018).
 Nevada’s Rules of Civil Procedure were significantly revised effective March 1, 2019.
 Justice Pickering dissented, arguing in part that the lawyer is an agent for a party and should be included within the list of those barred from effectuating service.