Coat large saucepan with a few sprays of olive oil cooking spray. Add the onions and cook over medium-high heat until they're soft and just starting to brown. Add the ground turkey and cook over medium-high heat, breaking up the meat with a spoon, for about 6 minutes or until no longer pink. Add tomatoes, pinto and black beans, broth, garlic, chili powder, oregano, cumin and mustard powder. Bring to boil over high heat, then reduce the heat to low. Cover and simmer for 20-30 minutes. Garnish with olives and scallions.