The best time to buy Nvidia stock this summer was well before its earnings report.Nvidia (NVDA -4.84%) last reported earnings on Aug. 27. That was another blowout report from the artificial intelligence (AI) chip leader. Revenue soared 56% year over year in its fiscal 2026 second quarter, and sales of its AI platform Blackwell to data center clients grew by 17% from the prior quarter.Yet Nvidia stock has only moved about 2% higher since that report as I write this on Oct. 7. That's not because investors wer ...