To be able to open this nornir chest, you’ll need to have Atreus’ light and shock arrows. You’ll get them both after completing the journey quests “The Light of Alfheim” and “Inside the Mountain”.
Rune Seal 1
Found in the shaft where you have to climb up to reach the witch’s garden. Impossible to miss.
Rune Seal 2
This is found beside the the sap-covered coffin, behind a small waterfall. You can destroy the rune using your axe. To reach the coffin, you’ll have to activate the light crystal under the platform you’re standing on to create a light bridge.
Rune Seal 3
This is found on a rock ledge right beside the hidden chamber of Odin.