Some Nosler brass is made by Norma. Some of their early stuff was made by Remington. They farm it out to who ever gives them the best price.
Maybe, but that "farming out" process also means the capability of meeting ready to load status.
Federal Gold Medal, Norma, Lapua and RWS are perhaps the few that have done such in recent memory.
Remington will mark brass made in different plants as the same "lot" number; along with not even being the same weight or capacity. I have examples.
Most Nosler brass I've used (204, 223, 264 WM,7RM, 300 Roy, 338 Win.) has pretty much matched corresponding Norma brass (same chamberings) in weight, capacity and ready to load status, ie chamfered mouths, uniform necks and case length.
Norma also makes every cartridge case that Nosler makes available, something that domestic manufacturers do not offer.