I worked as a telephonic & field case manager for a regional case management company for about 5 years. They contracted with insurance carriers such as GAB Robins which insures employers and individuals for workers comp & disability. I've worked some files for GAB Robins for field case management. The offices I worked for were in NJ & NY.
Several big insurers have started hiring in-house telephonic case managers over the years and have them covering red-flag claims in several states. Depending on how they have the position structured and what territory you would be expected telephonically, you many need to apply for out-of-state licensure in the area you would be covering.
I currently work as a hospital case manager and have really come to despise insurance companies because of the restrictions and denials they place on "reasonable & necessary" medical care. It gets very complicated. I could never bring myself to work at one of those places, but that's just me. It's like working for the enemy while still trying to be the good guy. The clients you work with tend to be very wary of "the insurance company", so it takes a great deal of diplomacy to convince them that your role is actually to be proactive for THEM and not the insurance company.
Just saw your message today and I see you posted in October, so I don't know if this is helpful.