Place the sweet potato on a rimmed baking sheet and pierce it a few times with the tip of a knife. Bake the sweet potato until tender all the way through, about 1 hour. Allow to cool slightly.
In a small skillet over low heat, warm the oil and garlic until the garlic is lightly browned and soft, about 10 minutes. Set aside to cool.
In the bowl of a food processor, add the cooled oil and garlic, chickpeas, almond butter, lemon juice and salt and puree until smooth. Scoop the flesh of the sweet potato into the processor and puree again until combined and smooth, adding 1 to 2 tablespoons water if needed. Remove the hummus to a bowl and stir in the za'atar, leaving a little swirl. Serve drizzled with olive oil alongside pita chips as desired.