Nickel coins minted in 1945 with the "P" mint mark were produced at the Philadelphia Mint. These nickels are relatively common and are not considered to be rare or valuable. In general, a circulated 1945 nickel with a "P" mint mark is worth around its face value of $0.05.
However, certain varieties or errors of the 1945-P nickel could potentially have higher values. For example, if the nickel is in uncirculated condition (meaning it shows little to no wear and tear), it may be worth a premium to coin collectors. Additionally, specific errors or die variations can also increase the value of a 1945-P nickel.
To accurately determine the value of your 1945-P nickel, it is recommended to consult with a professional numismatist or coin dealer who can examine the coin in person and provide an accurate appraisal based on its condition and any unique characteristics.