I like the chaff idea in terms of keeping with what Darths & Droids has established regarding how hyperdrives work, but in this particular scenario, I must agree with Memnarch in saying that it's utterly implausible that the First Order fleet could have deployed it this quickly. They'd need to be machine-gunning the chaff actively, at the sort of velocities that make the chaff into projectile weapons, in the Resistance's direction in order to get it in front of them.