C-axis-oriented NdBa₂Cu₃O_7−δ thin films (thickness ~ 2000 Å) on LaAlO₃ substrates have been prepared and irradiated with Ag⁺¹⁴ (200 MeV) ions at different inclinations (θ_d=0°, 15°, 30°, and 45°) to the c axis. Magnetization-field hysteresis loops have been obtained on pristine and irradiated thin films at two different temperatures in applied magnetic fields up to 5 T. Estimates of the critical current density J_c(H,θ) and the volume pinning force F_p(H,θ) from the magnetization data reveal a strong dependence on track inclination. An increase and a subsequent saturation in F_p(H,θ), instead of the usual Gaussian peak around the equivalent matching field, B_Φ, is observed. It is suggested that this dependence of J_c(or F_p) on θ_d is a consequence of the effective modification of vortex pinning by tilted columnar defects.