As we know from the Magic 2014 set announcement on the mothership, Chandra Nalaar is going to have a prominent role in the upcoming core set, since there doesn't seem to be a monored planeswalker fit to replace her. (Though Tibalt, the Fiend-Blooded is an option in theory, his only version has proven rather unpopular as a card regardless of how players feel about him as a character.) So far, the only thing we know about this year's core set is that Chandra is getting a new card version (she's so far had three - the original, Chandra Ablaze, and Chandra, the Firebrand). The promotional art from the announcement, featuring the fiery planeswalker blasting her way out of a fortress gate, still may be used on a card, but the perspective doesn't seem right for a planeswalker card; it looks instead like an instant or sorcery that is thematically related to Chandra.
However, in the background of the Pro Tour Gatecrash online stream, various viewers have spotted what looks like a poster with new art of Chandra on it. MTGSalvation user MasterJace2019 pointed this out in a rumor mill thread with screencaps of the background art. In this new art, Chandra appears to be lunging, and her goggles are glowing with the same fire that normally engulfs her hair when she uses her spells. Whether this could go on the new Chandra planeswalker card or simply yet another Chandra-related card remains to be seen, but it definitely looks like she is the main focus of the artwork.