Pirates of the Caribbean: Dead Men Tell No Tales saw the return of Davy Jones in a post-credits scene, but he's not played by his usual actor Bill Nighy. Based on the nautical legend and teased in the first Pirates of the Caribbean movie, Nighy first appeared as Jones - under a sea of CGI - in the second installment, Pirates of the Caribbean: Dead Man's Chest. He returned again in At World's End, which saw Orlando Bloom's Will Turner replacing him as the captain of the Flying Dutchman, and was then absent completely during On Stranger Tides.
2017's Pirates of the Caribbean 5 attempted to steady what had been a rocky franchise ship, if not a sinking one; it brought in some fresh blood in the way of directors Joachim Rønning and Espen Sandberg, as well as new cast members such as Javier Bardem, Brenton Thwaites, and Kaya Scodelario, alongside returning figures like Geoffrey Rush's Captain Barbossa and, of course, Johnny Depp's Jack Sparrow. While Disney may now be choosing to reboot Pirates of the Caribbean after the fifth movie didn't inspire a new wave of interest in the saga, it was clear that the ending of the fifth movie was setting up the future, not least with the tease of Davy Jones' return.
The post-credits scene of Pirates of the Caribbean: Dead Men Tell No Tales takes place in the bedroom of the returning Will Turner and Elizabeth Swann (with Bloom and Keira Knightley both returning), as the silhouette of Davy Jones enters their room and makes to attack them. Will makes up and Jones disappears, suggesting it was a dream, but the wet floor hints otherwise. Whatever the truth, Nighy wasn't even informed of his role in Pirates of the Caribbean 5, only learning of it from a cab driver after it had released. With Davy Jones only in silhouette, however, it makes sense that Nighy wouldn't be asked back.
Davy Jones is a complex motion-capture CGI character, which means he's going to be expensive to put on screen properly. Similarly, Nighy coming back would further that cost, since it would mean increasing the work going into creating it for what's a very brief scene. While Disney isn't exactly in a position where it needs to be overly stringent, it also doesn't make sense in terms of the financials or the production schedule to have an actor return and perform motion capture for a scene that was just as effective in silhouette.
For his part, Nighy did note he'd be happy to return to the franchise in future, though that's a possibly that looks far less likely right now. While Davy Jones is the kind of character who could be re-used in a reboot, his storyline setup here is tied to characters who may no longer be used, which would render it moot. There's still some potential in the character, but as Pirates of the Caribbean 5 may have been the last in that continuity, he might have to forever stay in Davy Jones' locker.