We've recreated this Italian classic with lots of flavor and very little fat.
Spray nonstick skillet with olive-oil spray; place over high heat. Sprinkle chicken with 1/2 teaspoon salt and 1/8 teaspoon pepper. Cook in skillet until browned on both sides, about 6 minutes. Transfer to a plate.
Wipe out skillet, and respray. Add mushrooms, and cook until browned, about 5 minutes; set aside. Reduce heat to low.
Respray skillet; add onions, celery, carrots, and garlic; cover, and cook, stirring, until onions are translucent, 7 to 8 minutes. Add wine, and raise heat to high; cook until wine is almost evaporated, about 30 seconds.
Add tomatoes, yellow pepper, rosemary, stock, and remaining 1/2 teaspoon salt and 1/8 teaspoon pepper; stir to combine. Add chicken and mushrooms; bring to a boil. Reduce heat to medium low, cover, and simmer chicken until tender, about 30 minutes. Serve immediately.