The California Department of Motor Vehicles (DMV) site states that nonresident military personnel, and both military or civilian members of NATO who are not citizens of the United States are permitted to operate a vehicle in this state with valid license plates from either:

A. the individual's home state or country or

B. the state or country where the individual was regularly assigned and stationed when the license plates were issued, if the following requirements are met:

1. The license plates displayed on the vehicle are valid plates issued by a foreign jurisdiction.
2. The vehicle registration and license plates are issued to the military person or spouse of the military person.
3. The vehicle registration and license plates are issued by the foreign jurisdiction where the military person was last regularly assigned and stationed for duty by military orders or a jurisdiction claimed by the nonresident military person as the permanent state of residence.
4. If the vehicle is a motor vehicle, the owner or driver has insurance.

The CA DMV notes however that military orders do not include military orders for leave, for temporary duty, or for any other assignment of any nature requiring the military person's presence outside the foreign jurisdiction where the owner was regularly assigned and stationed for duty.

This section applies to all vehicles owned by the military person or spouse except any commercial vehicle used in any business manner wherein the military person or spouse receives compensation.

California defines nonresident personnel as any nonresident owner of a vehicle registered in a foreign state and a member of the U.S. armed forces or spouse of a member of the U.S. armed forces on active duty within this state. Any person on continuous active duty in the Air Force, Army, Navy, Marines or Coast Guard is considered military personnel. This does not include civilian personnel employed by a branch of the armed forces.

The Nevada DMV states that Nevada residents on active duty in the U.S. Armed Forces may maintain a Nevada vehicle registration while stationed in other states. They go on to note that if your registration renewal requires an emissions inspection and you cannot have it completed in Nevada, you must have it completed if you are currently residing in an area out of state that requires emission inspections, which CA does.

So it would appear that you could leave your registration and insurance in Nevada since you are a nonresident of California, just a military person stationed in CA. You would however need to check with your insurance company and make sure they will properly insure you in California with your car's registration still remaining with Nevada.

If your insurer wants to transfer you to a CA insurance company then you may need to register your car there since Nevada requires car insurance coverage must be reported by an insurance company authorized to do business in the State of Nevada and that you hold a Nevada Evidence of Insurance card.

Speak with your insurance agent to make sure you are properly covered in California as a nonresident military member stationed in CA. To get specific questions about California registration and insurance requirements while you are stationed there contact the CA DMV whose representatives should be able to help you determine if you can keep your license, registration and insurance in Nevada or if any of these items need to be changed over to abide by California laws.