In a large saucepan, over medium heat, cook onion for 5 minutes or until tender but not browned.
Add beans, chicken, stock, rice, corn, salsa, lentils, sweet pepper, chili powder and garlic; bring to a boil.
Reduce heat, cover and simmer 20 to 25 minutes or until rice and lentils are tender and most of the liquid is absorbed.
Serve over tomato slices, if using.
