Jefferson nickels have been minted since 1938 and at three different mints so that's a VERY broad question. For a specific coin's value, please look for questions in the form "What is the value of a (date) US nickel?"
5 cents. The majority of Jefferson nickels are only worth face value.
Modern nickels are normally called Jefferson nickels because they have a picture of Thomas Jefferson on them, not Washington. There's more information at the Related Question linked below.
Please check your coin again and post a new question. Buffalo nickels were made from 1913 to 1938. All 1955 nickels are Jefferson nickels.
The reason they're called Jefferson nickels and Washington quarters is that Jefferson is on the nickel and Washington is on the quarter. In any case 1946 is not a rare year for nickels, see the Related Question.
1958-D Jefferson nickels are still found in circulation and are face value.
Jefferson nickels are quite common and generally have no special value beyond their five cents face value. The exception would be if you found a coin that was printed wrong at the mint or otherwise was very rare and in good condition. in which case it might be worth more.
The only nickels to contain silver were the so-called war nickels minted from mid-1942 to 1945. Other post-1950 Jefferson nickels are worth face value unless they're in uncirculated or proof condition.
The last buffalo nickels were minted in 1938. All 1939 nickels carry the familiar picture of Thomas Jefferson.
US Jefferson nickels dated 1963 are still found in circulation and are only face value.
5 cents. Only a small handful of Jefferson nickels are worth more than face value, such as the 1942-45 silver war nickels, and the elusive 1950-D.
Please check your coin again and post a new, separate question. Buffalo nickels were made from 1913 to 1938. All nickels minted since 1938 are Jefferson nickels.
???? Monticello is on Jefferson nickels struck from 1938 to 2003 and 2006 to the present.