Intervening Ni II absorption at z_abs ≈ 1.77 in the TXS 1331+170 spectrum (black curve) and simultaneous fit to the four 1370, 1709, 1741, and 1751 Å transitions (red curve), using our estimated f-values. This fit is overlaid on the Ni IIλ1317 absorption profile, which is affected by weak Lyα absorptions blueward and redward of the main component. At v_helio = 0 km s⁻¹, the redshift is z = 1.77638