From ọlá ("honour, prosperity") + ń rìn ("is moving") + iwájú ("ahead"): "honour moves forward" / "prosperity is advancing." Shortened to Nre or Waju.
Source: Yoruba oríkì surname, cross-referenced across the DiscoverYorùbá surnames guide and the ọlá- pattern attested in 0043 (Ọláwálé, yorubaname.com)