On a lined baking sheet, place the sweet potatoes toss with olive oil, cumin, salt and pepper. Bake for about 20 minutes until tender and slightly crisped. Remove from the oven and set aside.
In a bowl, mix the corn, beans, cilantro and lime juice. Set aside.
In a decorative bowl of your choice, arrange the lettuce and top in sections with the sweet potatoes, black beans, corn, shredded chicken and avocado.