Other than Data dying and backing himself up in B-4, I don't see any similarity between TWOK and Nemesis. People have been saying this on here for over 20 years, but one similarity doesn't make the two movies alike.
"Revenge!" isn't enough. That's been a concept in movies since long, long, long before TWOK even existed. And Shinzon gets his revenge right at the beginning of the movie when he dissolves the Romulan Senate. After that, he's not motivated by revenge. He just wants to conquer. Whereas in TWOK, Khan's revenge is never satisfied, since he can't get Kirk, and he has no further goals because that revenge has completely blinded him.
"Time marching on!" Technically true, but still not the same. In NEM, the crew are going their separate ways. In TWOK, everyone except Chekov is on the Enterprise, he finds his way back, and it doesn't look like anyone's going their separate ways.