Preheat oven to 350°F. Heat oil in large skillet on medium heat. Add onion and bell pepper; cook and stir 3 minutes or until softened.
Spread 1/2 of the bread cubes in 13x9-inch baking dish. Layer with 1/2 each of the onion mixture, beans, Cheddar cheese and Monterey Jack cheese. Repeat layers.
Beat eggs in medium bowl until foamy. Add milk, chili powder, oregano, cumin and salt; beat until well blended. Pour evenly over top. Press bread cubes lightly into egg mixture until completely covered. Let stand 10 minutes.
Bake 40 to 50 minutes or until center is set and top is golden brown.