Not a very fun match IMO, it's just so lopsided. That said, I have many times found ways to lose this match with Jax, and yet also, pulled out wins vs elite Jaxs with Scorpion. I believe Scorpion is the best ninja of the 3 to take down Jax (that isn't saying much) and he ain't got nuthin' to lose in this one.
SCORPION
Scorpion must be agressive, absolutely. You might as well just concede the match if you're going to try and out-turtle Jax. Just go crazy with sweeps and jab (or whatever it is Scorpion has up close). Time teleport punches precisely, and try to use jump-around kicks to pressure Jax into jumping into your air throws. Probably will be all for naught against a great Jax, but it's your only real chance with Scorp. Spear will just get blocked and punished with a ground pound, but throw a few to keep Jax honest.
JAX
Don't jump. LOL. With golden punches, MGPs, his anti-air HK, etc etc etc... Jax should be just fine. Using ground pound, wave punch and AA's, Jax can turtle all day to win. But he can also be aggressive up close, something he can't do too successfully against many of the other fighters. Land a hammer punch i.e., and that's pretty much the round right there after you take your next free hit.
Overall 9-1 for Jax. I'm guessing the best Scorpion vs the best Jax would be hard-pressed to even get 1 win out of 10.