The opportunity in AI remains massive.Artificial intelligence (AI) has been the driving force behind the stock market's biggest winners in recent years, and that trend looks far from finished. The opportunity ahead is still massive, so this is an area that most investors will want some exposure to.Here are five top AI stocks to buy as September rolls on. 1. NvidiaNo company has benefited more from the buildout of AI infrastructure than Nvidia (NVDA 0.43%). Its graphics processing units (GPUs) remain the gol ...