Drizzle chicken breasts with olive oil and sprinkle with salt, pepper, and oregano. Cook chicken with your favorite method, either sauteing on the stovetop, baking in the oven, or grilling. I typically saute in my iron skillet or bake in an aluminum foil packet at 350 degrees F for 15-20 minutes. (Make sure chicken is cooked completely, whatever method you choose.) Dice cooked chicken into bite-sized pieces. Allow to cool slightly to avoid wilting greens.