2022 D Nickels With A Large Die Crack. I Think.

has the general appearance of a clash mark, but there's nothing on the reverse that lines up to make such a clash

if that's a die crack. I'd expect to be visible on the date, but the pics make it seem the anomaly is visible only in the field around the date

I have a half dollar with 2 similar arcs on it that fit the diameter of a half dollar perfectly.

that was my thought initially. like maybe a previous planchet might have not been fully/properly seated, or maybe a partial/damaged planchet damaged the die previously, but it kind of ends at the '2' and there is no damage to the reverse, so I thought maybe not.

maybe it's strikethough damage to the die and there's a nickle out there somewhere with a key ring embedded in it... :p

actually, I've looked at that more closely and it seems to line up, which means it would also line up with the die, and since the obverse/reverse dies aren't a fixed set, even if both dies were damaged, they could have just forgotten to replace the obverse die. or maybe it was just a friday... "eh, good enough... let's go get a beer."