Place beef, turkey and onion in a large nonstick skillet over medium heat. Cook, breaking up the meat with a wooden spoon, until cooked through, about 10 minutes. Transfer to a colander to drain off fat. Wipe out the pan. Return the meat to the pan and add tomatoes, cumin, ground chipotle (or chili powder) and oregano. Cook over medium heat, stirring occasionally, until most of the liquid has evaporated, 3 to 6 minutes.