If the iPhone is dead, people specialized in data recovery from iPhones can try to "wake up" the iPhone just enough to pull a back-up (Android phones such as Samsung or Nexus or Sony, etc. require a different approach). We do this often and many times were able to get pictures and contacts from iPhones thought to be dead. Sometimes the phones were sent back in working order.
But if the data has been erased and/or replaced by new or older data, you cannot get it back.
As for the original question, it is not possible to just pull the NAND from the iPhone and read it. It has to be paired with other components (depending on the iPhone model, those components vary). If you are skilled enough, you may then transfer all the critical components together to a working board. But that's not guaranteed to succeed since the components may be damaged before or during the transfer process. And the level of skill required to succeed is very hard to attain.