Some locations of chests in Skag Gully.
Location 1 & 2: Nine Toe's room (White Chest) (Red Chest)
Nine-Toes' lair contains two chests. A red chest is on the "stage" where Nine-Toes appears. A white chest can be found on the elevated area to the right of Nine-Toes' stage.
Location 3: Bridge (Red Chest)
Follow the land bridge located SW of the entrance to Skag Gully.
Location 4: Scar Mountain (Red Chest)
A red chest can be found in the encampment where Scar is found.
Location 5 & 6: Bladeflower hunting (Red Chest x2)
Two red chests can be found in the cave system. The first red chest is near the first Skag den you see. Go past the bushes to find a hidden cave section, which contains a red chest. The other red chest is found at the end of this cave system.