could be a XCX port, or it could be a new Monoloth game. but IMO they shouldnt announce projects way to early. they announced XCX waaaaay too much in advanced, and it took a long time to get it out.
They could be reusing Xenoblade X's engine and assets for this new game. In fact I think one of the reasons why it took a while for X to come out was cause they were building the engine from scratch so this shouldn't take as long to make.