McAlister's Chicken Tortilla Soup #2

McAlister's Chicken Tortilla Soup #2
2 boneless, skinless chicken breast halves
1 1/2 teaspoons olive oil
1/2 medium onion, minced
2 tablespoons minced garlic
1 teaspoon chili powder
1 teaspoon dried oregano
1 (14.5-ounce) can crushed tomatoes
1 (28-ounce) can low-sodium chicken broth
3/4 cup plus 2 tablespoons water, divided
1/4 cup cornstarch
1 (4-ounce) can chopped green chiles
4 ounces shredded Cheddar cheese (about 1 cup)
1 tablespoon chopped fresh cilantro
2 cups tortilla chips
1 bunch green onions, sliced
Bring about 1 inch of water to a boil in a skillet large enough to hold the chicken in a single layer. Add chicken, reduce heat to a simmer and cook until chicken is done, about 15 minutes. Drain chicken; cut into 1/2-inch cubes. In a medium stockpot, heat oil over medium heat. Add onion and garlic; saute until soft. Stir in chili powder, oregano, tomatoes and their liquid, chicken broth and 1/2 cup plus
2 tablespoons water. Stir together cornstarch and remaining 1/4 cup water; stir into stockpot. Bring to a boil, then reduce heat and simmer for 5 to 10 minutes, until broth is slightly thickened. Stir in chiles, cheese, cilantro and cooked chicken. Stir until cheese melts, then let simmer for 10 minutes. Ladle soup into bowls; serve chips on the side (or crumble a few chips over each bowl of soup). Garnish with chopped green onions.