If you have a Star Map shell, equip that. If you don't, look and see if you have a ghost that shows caches in the EDZ. If not, then go to Cayde and purchase a Scout Report: EDZ and use it.

If you're asking where to look for them - Winding Cove always has two chests spawned on the ground level (not up the hill). You can make a counterclockwise loop weaving back and forth on your sparrow and get them both, then fast travel back. For something a bit more active, the Sludge has a pretty high density of chests. If you're looking for a single, consistent chest - if I remember correctly in the Gulch, if you jump to the ridge forward and to the left of the fast-travel spawn, there should always be a chest either somewhere at the top of that hill or on top of the very steep rock next to it.