The Christian St Nicholas character is, well, Christian. And we’re not.
One of the several pagan origins of the tradition of some character visiting all the children in the night and giving presents, was La Befana, an Italian witch. However, as this website points out:
In many cultures the relations between grown-ups and children is based on the observance of rules achieved through the fear of punishments and expectations of reward.
And we try not to parent in that way.
Santa Claus is a symbol of consumerism, greed, and too many toys. While it may not be true that the Coca-Cola Company dressed him in corporate red, I find it impossible to disassociate that image from the fizzy giant and all their misdemeanours.
On the whole, we try not to lie to Bernard. If we tell him fairy tales, we will explain that they are stories. When we talk about why people celebrate christmas, we will explain both the mythology of the birth of Jesus, and the fact that most people in this country are not celebrating said birth when they celebrate at christmas-time. But when parents pretend to their children that some strange man has broken into their home and left toys at the end of their beds, they do work quite hard to prevent the truth from coming out. How then do I explain about Say No To Strangers?
I know this sounds curmudgeonly. But I’m not saying Bernard won’t get presents, and I’m not forbidding the grandmothers from doing christmas stockings, as they both feel morally bound to do. But I will tell the truth, including the fact that the stockings will be provided whether he is good all year or not.
Sorry Bruce.

I love the way you’re raising Bernard…you’re going to be my role model if I ever have any littles.
Also, I suppose, define ‘good’ in the sense of ‘good all year’. After all, I’m still getting ‘is she a good baby?’ all the time, i.e. does she cause you virtually no discernible disruptions in your otherwise carefree life, allowing you to resume the life you lived before she was born without a second thought.
Can you sense the bitterness?
Well quite; if the commonly held definition of “good” is “compliant,” then Bernard is definitely not good. But if it is “curious, enthusiastic, bright, energetic and strong-willed,” then yes, maybe…
Yes – for ‘good’ here, read ‘asleep from 6 in the evening to 8 in the morning… and no, not very compliant either, though your adjectives sound both familiar and more desirable anyway.
I so agree with you – why does celebrating a festival have to be tied in with someone being ‘good’? It is a time to be with family and friends enjoying themselves. Is their behaviour going to be the main reason for joining in things – heavens I can see why lots of children behave ‘badly’ before going to school – or hang on, does that tactic not work!!