The Mint produced over 28 million Nickels in 1868, making this the second most common date in the entire series. At the same time, the Mint made Half Dimes, but only to the tune of 88,600, a seemingly insignificant mintage in relation to the Nickel (a good question is why they were even made at all).
Mint State 1868 Nickels are readily available in grades up through MS65. There are enough MS66 examples to fill the PCGS Condition Census with coins of that grade, but PCGS has not assigned a higher grade to any 1868 Nickel.
This date is usually struck well, though cracks continue to plague many examples (to see a variety of interesting die cracks, check out the View All Coin Images link above, then click on the individual pictures to get a dramatic close-up look.