well first of all through historical records saint nichloas was an existing person, also normallay gifts given by santa are normallay gifts that would be pricey and parents wouldn't be willing to pay for a gift over $100, also every Christmas Eve, presents mysteriously appear under the tree with your name on them. How could your parents know what you wanted for Christmas unless they were getting help from someone who knows everything about you?
Additionally, many people around the world report seeing Santa Claus on Christmas Eve.
It would be pretty difficult for your parents to coordinate all of those sightings!
Honestly if you are a non-believer your opinion dosen't dictate his pretty much guaranteed exsistence