Nvidia has led the S&P 500 ( ^GSPC -0.29%) higher this year amid frenetic interest in artificial intelligence (AI). The stock has surged 136% since January, and Wall Street analysts forecast median upside of 30% from the current share price of $115. But betting on a single AI stock is a bad strategy.

These three small-cap AI stocks have a shot at generating millionaire-making gains over the next decade: SoundHound AI (NASDAQ: SOUN), Serve Robotics (NASDAQ: SERV), and Evolv Technologies (NASDAQ: EVLV). Image source: Getty Images.

The central bank's decision to slash borrowing costs by 50 basis points is easing concerns about the economy. That could lift the AI trade.

Nvidia has been a bellwether in the artificial intelligence (AI) space thanks to its graphics processing units (GPUs) that have played a crucial role in the training and deployment of AI models. But the stock has fallen out of favor of late as investors are worried about its slowing growth.