Technically they did not, no; Nacretinei survives long enough to be known to the Imperium, after all, however, your assistance likely spared the Masque of Burning Groves significant casualties, prevented Nacretinei's fleet and their allies' forces from being completely destroyed covering their escape, and helped the remaining infiltration of the Craftworld itself be resolved more quickly, with the attending reduction in infrastructure damage and personnel losses. In short, they could have done it without you, but the cost would have been far higher, so do not think you made no or little contribution here.