For Nevada to recognize a states CCW they only need to "have an electronic database which identifies each individual who holds a valid CCW permit, issued by that State, in which Nevada law enforcement may access directly at any time". That statement was from a NV DPS representative back in 2021 (see here).

They do not necessarily need to have a written agreement. This can be found in NRS 202.3689 (Department refers to the Nevada Department of Public Safety/DPS):

NRS 202.3689  Department to prepare list of states that meet certain requirements concerning permits; Department to provide copy of list to law enforcement agencies in this State; Department to make list available to public.

1.  On or before July 1 of each year, the Department shall:

(a) Determine whether each state requires a person to complete any training, class or program before the issuance of a permit to carry a concealed firearm in that state.

(b) Determine whether each state has an electronic database which identifies each individual who possesses a valid permit to carry a concealed firearm issued by that state and which a law enforcement officer in this State may access at all times through a national law enforcement telecommunications system.

(c) Prepare a list of states that meet the requirements of paragraphs (a) and (b).

(d) Provide a copy of the list prepared pursuant to paragraph (c) to each law enforcement agency in this State.

2.  The Department shall, upon request, make the list prepared pursuant to subsection 1 available to the public.

Just following up with you. I did a small amount of research, nothing too in-depth but this is what I found from the Nevada Sheriff's and Chiefs Association (NVCSA) that may explain why (maybe?):

According to their policy: "In complying with this federal law, it is important to note that this process does not provide the law enforcement retiree with a concealed firearm permit nor will any law enforcement agency give the law enforcement retiree the right or ability to carry their firearm concealed. The ability to carry a concealed firearm when crossing state lines is granted by LEOSA itself and the only responsibilities given to Nevada law enforcement agencies are to facilitate the firearms qualification and to conduct a criminal background check for retirees."

This can be found here: https://img1.wsimg.com/blobby/go/3976e12a-da21-4fa4-b94b-5f48dff7a7b7/downloads/1d1f55ruv_834839.pdf?ver=1662483402691. If that doesn't work go here and under Concealed Firearm Permits (aka CCW) click on LEOSA Retiree Package.

Anything else, like what you are asking for, would have to go through the Nevada State Legislature. I would suggest reaching out to one of the pro gun/pro police representatives like Gregory Hafen or Ira Hansen (just to name a couple).