How much is a 1801 US Nickel worth?

The U.S. did not mint nickels until 1866.

Please check your coin again and post a new question with more details that help to ID it. If the coin says "half dime" on the back it's not a nickel even though it's worth five cents. The half dime was a different series. If it's the size of a modern nickel you may be reading the date incorrectly.