David Nelson sees three key catalysts driving the S&P and Nasdaq to record highs: clarity on the final tariff structure, reduced geopolitical risk, and a favorable yield curve. Nelson believes these factors have shifted market sentiment, making it a good time for investors to be in equities, especially with lower yields. He also likes L3Harris Technologies Inc. (LHX) and Capital One Financial Corp. (COF) due to their exposure to growth areas like defense spending and financial technology.