Here is the Nevada NRS. The law is not called Brandishing in Nevada:
"NRS 202.320 Drawing deadly weapon in threatening manner.
1. Unless a greater penalty is provided in NRS 202.287, a person having, carrying or procuring from another person any dirk, dirk-knife, sword, sword cane, pistol, gun or other deadly weapon, who, in the presence of two or more persons, draws or exhibits any of such deadly weapons in a rude, angry or threatening manner not in necessary self-defense, or who in any manner unlawfully uses that weapon in any fight or quarrel, is guilty of a misdemeanor.
2. A sheriff, deputy sheriff, marshal, constable or other peace officer shall not be held to answer, under the provisions of subsection 1, for drawing or exhibiting any of the weapons mentioned therein while in the lawful discharge of his or her duties.
[1911 C&P § 174; RL § 6439; NCL § 10121]—(NRS A 1967, 486; 1989, 1240)"
The key words are "rude, angry or threatening manner".
Just note, if you are defending yourself, you CAN draw your weapon. We see a lot of "what if's" posted on these forums. One recently was "if I'm walking down the street and a suspicious guy crosses the street, seeming to intercept me, can I draw my weapon?" The answer is yes. There is no law that says you can't pull your weapon out of it's holster. Keep it at your side, pointed at the ground until you need to target.
"Can I aim my weapon at the suspicious person?". Yes, if you are in a mode of defending yourself.
Defending yourself doesn't always mean shooting somebody. There are things that hopefully happen along the way that will determine if the "bad guy" just goes away, or proceeds with his/her intent and you have to shoot them to stop them.
My advice?
1. Take a good self defense class.
2. Know how to defend yourself and what your legal rights and responsibilities are. Too many people own guns and don't know what they can/can't do legally to defend themselves.
3. Don't try to defend yourself with you keeping weapon holstered until the last moment, and then get the bad guy, quick draw style. You'll surely lose.
For your rifle, carrying it to your car slung, or in your hand does not matter. Just remember, in Nevada, when transporting in a vehicle, you may have rounds in the magazine, in the rifle, but NO ROUNDS IN THE CHAMBER! That's more of a law on the Hunting and Wildlife side of the NRS. Helps prevent poaching.