In a tweet, Kuo said that the 6.1-inch "iPhone 14 Pro" and the 6.7-inch "iPhone 14 Pro Max" will get the A16 chip, while the 6.1-inch "iPhone 14" and the 6.7-inch "iPhone 14 Max" will retain the same A15 chip from the iPhone 13 lineup.
While this would be a first, it does seem reasonable. That said, I would expect Apple to increment the processor name a bit. A15X is most likely, as they never used this for an iPad this year and it would make the lower end iPhone still feel fully new. Maybe there will be more GPU cores active or more RAM, but raw performance will be largely the same as the A15 we have in the iPhone 13 lineup.