Josh Brown of Ritholtz Wealth Management highlighted the critical importance of the market's reaction to Nvidia's upcoming Q4 earnings report. Nvidia, having led market gains in 2023 with a 239% increase due to optimism around AI, faces high expectations. Despite potential strong earnings, Brown warns that an underwhelming market reaction could negatively impact the Nasdaq. He referred to Nvidia as 'the most crowded trade on Earth' and suggested that even a great report resulting in a modest share price increase could psychologically damage tech sector sentiment. Nvidia shares and the Nasdaq have already seen declines since Brown expressed concerns about market tops.