As a Plat ADC main I, myself, find Jax to be nuisance due to his ability to gap close with his Q and Flash. Although if Jax attempts to prep his counterstrike in order to stun you, he has effectively used his only source of defense against you. (He can no longer "dodge" your auto attacks)
My suggestion is to play champions that have some sort of mobility to get out of stun range, such as
or even block it with Sivir's spell shield. I personally believe that Sivir hard counters Jax due to her mobility with her ult and her spell shield.
Nasus on the otherhand has no gap closer other than his Flash, therefore kite him out and if he decides to use wither on you hope that your teammates either peel for you or purchase a QSS and continue kiting him out.
And if all else fails, tell your teammates to ban one of the in champ select chat while you ban the other.
Hopefully my advice is somewhat useful. Good luck bud