These companies' investments in artificial intelligence (AI) could help them -- and investors -- win big.The Nasdaq roared to a record high earlier this year, confirming the presence of a bull market. But it didn't stop there. The index continues to climb, just recently reaching yet another new high as investors pile into technology stocks and other growth players. This is great, but if you're looking to buy tech stocks, you might be wondering if valuations have become too lofty.I've got good news for you: ...