over James asking him to demonstrate his swing. He doesn't have his memory as of the last seven years, so why would that mean he can no longer make contact with a baseball? It just doesn't add up. I went back and watched those scenes and he is absolutely uncomfortable and tried to shift it to Coach Kai.
Here is my breakdown on the possibilities:
A Twin - Remember, Liesl gave Nathan to Madeline to raise, so that he would have a better life. He and Nina are actually cousins but grew up believing they were siblings. So if Liesl had twins, who raised the other baby? There is no way she would have given him to Faison. Why wouldn't Liesl ever make reference to a twin out there somewhere? Identical twins share the same DNA but not fingerprints. That would explain why he told Lulu a mismatched story of his upbringing. This is my second choice.
Imposter - I think this is the most likely. I don't think it's a rubber mask. I think he either had plastic surgery or he's simply a doppelganger that was found. That would also explain why he told Lulu a mismatched story of his upbringing.
Nathan with His Brain Scrambled - This is my third choice. Something has been off with him since he returned. This would explains why the fingerprints and DNA matched. All I know is, I better not see a tarot card. ðŸ¤