What year was the first US nickel made?

Answer 1

The first US nickels were issued in 1866.

Before that, the 5¢ denomination was provided by a tiny (14 mm) coin called a half-dime that was minted from the same 90% silver alloy as dimes, quarters, halves, and dollars.

Nickel metal wasn't generally used in coins prior to the 1860s because it's so hard that it caused coin presses to wear out quickly. By that time improvements in Metallurgy let the Mint create dies were strong enough to tolerate nickel's hardness. The new 5¢ coins were made of an alloy of 25% nickel and 75% copper, the same composition used today for the denomination as well as the outer cladding of higher denominations since 1965.

Nickel 5¢ coins were popular because they're more convenient than the tiny half-dimes and lasted longer in circulation. Half-dimes were produced until 1873 when the denomination was eliminated as part of broader coinage reforms.