He has better-than-typical odds of clearing the standing hurdle. He was directly harmed, right.
But he's going to have some pretty high evidentiary hurdles, right? Discovery may well turn up that Nextar pulled his shows preemptively, both because of political affiliation and because of an upcoming merger. They didn't need to be "jawboned", and there's not much indication that they were even contacted by the FCC.
When the largest affiliate network in the country pulls your show, it's harder to make the case that ABC itself was responding directly to the FCC, which is what Kimmel will need to establish.
These are positive and not normative arguments and my confidence level is extremely low.