I would do nothing. You don't want to tell the CRAs to call off the dogs, and then find out Chase never reported the delete to them. I don't think there's an option to un-dispute. Wait and see what happens.
I just disputed two days ago to the CRA's about a 30 day late from chase back in Nov 2002. I called chase and they realized it should have not been reported and they are sending in a request to delete (they will send me a confirmation letter in 7-10 business days). I just need to know, do I wait or call up the CRA's and let them know to drop the dispute and they will receive something from chase soon.