Is there any difference at all in playing 2.Nc3 or 2.Nf3 in the Two Knights of the Caro-Kann? On Lichess, why is 2.Nc3 the second most common move in the Masters database, and 2.Nf3 played almost one-third as much?
One thing I can think of is that after 2. Nc3 you still have a chance to transpose to main lines after 2 ... d5 3. d4, so it's a tad more flexible. I know it's a stretch, but if your opponent is (for whatever reason) afraid of the two knights variation, they might not play 2. .. d5 and opt for 2. ... g6 or other inferior move.