A friend of mine has a US Nickel dated 1947 that seems to be stamped on Penny "copper" or whatever alloy is/was used. The coin is standard Nickel size. It seems to be thinner on one side and the stamp is offset a bit so that some of the stamp is missing. It is definitely not a "normal" coin. I'm wondering if this might be a rare misprint? Also, how would one get it accurately evaluated? Thanks!
First you should have the coin weighed. If it weighs exactly what a 1947 cent weighed (3.11 g) then you may have a genuine error (nickel struck on cent planchet). If not then you have something else. Can you post pics?
Post some pics here would be the first choice. Follow up with a reputable dealer. If the above sound promising, spend money to have it graded by a third party grading company.
If the weight is right (3.11 grams +/- .1 grams) then the chances are quite good that it is real. Pictures would help. I don't agree with the suggestion that you should have it slabbed because the cost would be a significant percentage of the value of the coin and a good error collector interested in it should be able to determine its authenticity well enough himself.