"If we leave, there will be chaos"
This is almost certainly true.
The problem is that it's akin to saying throwing a dozen eggs at someone and then saying that if they don't stand still and catch them all, there'll be a hell of a mess.
That's both true and irrelevant, and the correct move is to duck, not flail around trying to catch eggs.
The chaos is inevitable at this point. It was probably inevitable from the moment Bush made the decision to invade Iraq with a postwar plan that might as well have been drawn in crayon on a diner's kids menu. It was certainly inevitable when Bush treated the postwar period as a patronage opportunity for well-connected Republicans.
Trying to ensure peace and stability is honorable, but it's too late for that. Using our soldiers' lives to try to push the inevitable collapse onto some other President's watch is contemptible.