This Bible contradiction is from the Skeptic's Annotated Bible.
God killed Uzzah at the threshingfloor of Nachon.
2 Samuel 6:6 View context
And when they came to Nachon's threshingfloor, Uzzah put forth [his hand] to the ark of God, and took hold of it; for the oxen shook [it].
God killed Uzzah at the threshingfloor of Childon.
1 Chronicles 13:9 View context
And when they came unto the threshingfloor of Chidon, Uzza put forth his hand to hold the ark; for the oxen stumbled.