This is a question that's been debated since the arrival of the first nightmare teaser, and we still don't have an answer. That being said, this latest image does provide some possible clues. For one, the barely visible animatronic near the hat clearly has a reflection. Does this mean that he or she is, in fact, real? After all, the word "nightmare" isn't found anywhere in this teaser, which means the creature might dwell in the realm of reality.
Should that be the case, maybe this animatronic is real and the rest are just hallucinations.