Preheat the oven to 425°F.
Coat a large roasting pan with a few spritzes of olive oil.
Layer the slices of lemon in the bottom of the pan.
In a large bowl, stir together the lemon zest, lemon juice, four cloves of the minced garlic and oregano.
Add the chicken; toss to coat.
Arrange the chicken in a single layer on top of the lemon slices.
In a medium-size bowl, combine the olives, sweet potatoes, and the remaining minced garlic; toss to coat.
Arrange the sweet potato mixture over the chicken.
Bake for 40-45 minutes, or until the chicken is cooked through and the sweet potatoes are soft.