The value of a $20 Amazon gift card in Nigerian Naira can vary depending on the current exchange rate. Exchange rates are constantly fluctuating in the foreign exchange market.

To determine the exact amount, one would need to check with a reliable currency exchange service or look at the prevailing exchange rate on financial platforms. Generally, the Nigerian Naira is subject to economic factors such as inflation, interest rates, and global market trends which all influence its value relative to the US Dollar.
When converting, it's important to ensure you are using a legitimate and trustworthy source for the exchange rate. This helps to get an accurate conversion and avoid any potential losses or unfair exchange rates. So, the specific amount of how much a $20 Amazon gift card is in Naira can only be precisely known by referring to the most up-to-date exchange rate at the time of conversion.