It is tight, these tight connections are always easier when you are dealing with an airport you know and can quickly navigate. Sitting as close to the front of the plane will be a big help. But delta sells the ticket because more often that not passengers make the connection. If your flight is on time you should make the flight. In this case there is a non stop KE flight from ORD. I am guessing it is more expensive so booking is not an option but there are alternatives from ORD so if your first flight is shown as delayed have the research done on alternatives that work for you and be prepared to try to try and deal with the issue while you are still at ORD if the later Seattle flight doesn’t work.