Tijuana Chicken

2 large boneless, skinless chicken breast halves
3 teaspoons olive oil, divided
1/4 cup finely chopped onion
1/4 cup finely chopped green pepper
1 (10 ounce) can no salt added tomato puree
1 tablespoon chili powder
1/4 teaspoon oregano
1/4 teaspoon ground cumin
1 (15 ounce) can red beans, including liquid
6 corn tortillas
4 ounces shredded Cheddar cheese
1/4 cup sour cream
1 cup shredded iceberg or romaine lettuce
1 medium tomato, chopped
1/4 cup diced avocado
6 small black olives, chopped

Cut chicken breasts into 1/2-inch cubes. Heat 2 teaspoons of the oil in large, nonstick skillet. Add chicken cubes and saut