Nilsson (Swedish) comes from Swedish Nils, from Latin Nīcolāus, from Ancient Greek Νικόλαος, from Ancient Greek λᾱός, from Proto-Hellenic lāwós, from Proto-Indo-European leh₂wos, from Proto-Indo-European leh₂- — to bark, howl; to be concealed.
Ancestry of “Nilsson”, step by step
Nilsson traces back through two separate lines of ancestry.