So St. Nicholas wear the same hat.
St. Nicholas & Santa ClauseNot really the same person.
In some villages in Belgium, St. Martin comes on November 11 instead of St. Nicholas on December 6. The difference is that St. Martin gives historical presents to the poor children and St. Nicholas gives presents to the richer ones. They come with the steamboat from Spain and give the children speculaas, mandarins and sweets. St. Martin & St. Nicholas also have helpers. These are the 'Zwarte Pieten'. Santa has elves.
Santa Clause is not really celebrated with us. We know him, but it's not him who gives presents. It's the family members.
The concept is the same. But the story is different.