A man very adept at writing 'prophecies' in such a way that they can be made to seem to fit a set of circumstances, if you turn them around to make them fit. Nothing I've read clearly seems to show he was psychic.
Nostradamus was a very unusual guy. All his so called prophesies were vague and were probably just his thoughts and opinions about his world at the time. They do not apply to anything after his time and besides know one can foretell the future because all future events are directly related to events that occurred before it.