Place first 3 ingredients in a zip-top plastic bag; add chicken. Seal and shake to coat.
Heat 1 teaspoon olive oil in a large nonstick skillet over medium-high heat. Add chicken; sauté 2 minutes on each side. Remove from pan; keep warm.
Heat 1 teaspoon olive oil in pan over medium-high heat. Add onion, oregano, red pepper, and garlic; sauté 3 minutes or until onion is tender. Stir in broth and Marsala wine; reduce heat, and simmer 1 minute. Add the chicken and olives; cover and simmer 10 minutes. Add the grapes; cover and simmer 10 minutes or until chicken is done. Serve over pasta.