a diesel electric sub is fine if it is where it needs to be....and not a long amount of time is needed to get your job done.....if it needs to travel distances to get to where it needs to be you cant beat a nuke....
plus with a nuke and hi tech silent drives, you can stay under for as long as the food holds out...and no one knows you are there....
Where do the Swedes plan to go? They aren't going to blockade the Port of Los Angeles with diesel boats. On the other hand, we aren't going to send any Carrier Task Forces into the Baltic if these things are waiting for them.