MARTINSVILLE, Va. — Ross Chastain was trying to comprehend what he had done nearly an hour after his video game move upended the Cup playoffs and thrilled a sold-out Martinsville Speedway while also leaving some drivers uneasy about such a maneuver and NASCAR officials pondering a possible rule change to make sure it never happens again. “It’s sinking in the we did something that no one else has ever done,” Chastain said of his last-lap, rim-riding run. But what to call the wall-hugging move was too difficult a question for him to answer. “I’ll check the Internet,” he said. It...