Entrance to Flyleaf Catacombs
As you approach the final chamber you might notice the skyshard to your left, up in the rocks. Backtrack a bit and take the left road to climb up.
As you go up you have to get rid of some mobs.
This is the exact location of the collectible. Remember, turn left before facing the end boss of the dungeon.
Sand Kingdom Moons - Super Mario Odyssey Power Moons