m_F322W2 vs. m_F606W − m_F322W2 CMD of proper-motion-selected members of NGC 6397, constructed using NIRCam data. The inset displays the Δ_{F606W–F322W2} vs. Δ_{F814W–F150W2} ChM, where black points represent NGC 6397 stars, and the orange points correspond to a simulated ChM for a single-population cluster. Red error bars indicate the typical color and magnitude uncertainties for stars in different magnitude bins.