After a blockbuster first half for U.S. equities, investors are entering the back half of 2026 with a more complicated picture. The Nasdaq 100 is trading near record highs, fueled by the AI-driven rally — but with elevated valuations, shifting Federal Reserve expectations, and geopolitical uncertainties in the mix, simply chasing momentum is no longer enough. That makes stock selection critical heading into Q3 and Q4. CNBC Pro screened the Nasda…