[mothered]

I have successfully refunded several nike sneakers
If I sell them now, also with my real data, can this cause problems?

Sneakers obviously don't have Identifiable details such as a serial/IMEI number, hence they cannot be linked to the original buyer - yourself.

As such, use fake details when selling.

Is it smarter to sell the sneakers through Craigslist?

Correct.

Or any other similar platform.