Artificial intelligence (AI) stocks have been delivering incredible gains to investors. And with so many companies using AI technology, there's no shortage of investment opportunities.While businesses involving new technology can be volatile, you don't need to take on outsized risk to get AI exposure. The four companies below are all highly successful and should be long-term winners. 1. NvidiaNvidia (NVDA 1.75%) is the largest AI chipmaker and the largest company in the world, with a market cap of $4.2 tril ...