Tofu Chili with Chicken

2 tablespoons olive oil
1 1/2 cups onions, diced
1 cup celery, diced
1 green bell pepper, diced
4 to 6 cloves garlic, minced
2 tablespoons canned green chiles, diced
1 teaspoon cumin seeds
1/2 teaspoon oregano leaves
1 to 2 tablespoons chili powder
1/4 to 1/2 teaspoon crushed red hot pepper (optional)
14 ounces firm Chinese-style tofu, frozen, thawed, drained and crumbled
2 cups black beans, cooked
1 skinless boneless chicken breast, cooked and diced
1 (15 ounce) can tomatoes in pur