There’s not that much on Nicholas of Myra. Let alone contemporary.

He himself left no documentary evidence. Starting in the 9th century there are 4 ‘lives’ of Nicholas, hagiographic biographies of the saint. One, vita per Michaelem, a second Methodius ad Theodorum, a third in Latin by John of Naples, and a fourth by Simon Metaphrastes. There is also mention in the popular Legenda Aurea.

There’s a tradition that Nicholas was at the council of Nicaea, but it’s very poorly attested once you look into it. Most contemporary references to him being there, and the infamous slapping of Arius, are totally unreferenced.