Really? If memory serves me it's actually a doubled die, but is often called an "overdate". Unfortunately, there's a fairly common crack that closely mimics it, but is in a slightly different position. Check it out. As for the OP coin, I do wish the photo was more detailed, but from what I can see this too appears to be in the incorrect position. Edited to add: http://www.pcgscoinfacts.com/coin/detail/84019
According to the Red Book a 1943-P War Nickel has a 3 over 2. You may have that but without close ups of the coin and a clear photo of the date we may never be able to tell. There is also a doubled eye for this date.
Here's a comparison - between the OP example and one courtesy of PCGS - that strongly suggests it is not the variety in question....
If memory serves me correctly, the overdate has a line just below the center of the 3 while the die chip has a line directly to the center of the 3.
Nope. Just s die crack which is a minor Mint error. No increase in value which should be about a dollar due to silver content. Not sure what the current price of silver is but it has dropped recently.
Although somewhat clearer, about the same as the last one. I'm sorry, but the conclusion simply isn't going to change. Consider it a learning experience.