We study the quantum interference in two-photon resonant nondegenerate four-wave mixing (NFWM) in a dressed cascade four-level system in which the two upper levels are coupled by a strong laser field. We find that in the presence of a strong coupling field, two-photon resonant NFWM spectrum exhibits Autler-Townes splitting, which reflects the levels of the dressed states. It also leads to either suppression or enhancement of the NFWM signal. This scheme involves the resonant three-photon excitation, therefore, provides a new spectroscopic tool for studying highly excited atomic states with high sensitivity.