I was wondering if there is a time limit after the water chip and it's with the mutant invasion is this true?

After you return with the chip, the time limit becomes 13 years. And that's just because the game will crash if you somehow manage to play that long.

W:hile there is no longer a time limit, individual results do have time limits due to the moving hordes of supermutants, so the longer you take, the worse the end results. You still win the game, though.