Latin American Street Food's Spicy Chicken Tostadas

Yum!  I really loved these, and we liked the ease of eating and making these.  Noah and Aaron gave it a perfect 10, and Owen and I gave these a 9, Owen because he said they were too spicy, and I just don't love chicken tostadas as much as just bean ones.  The Latin American Street Food cookbook came up with a real winner for our family this time.  We split this meat into 12 servings, and each serving was 77 calories.

1 T vegetable oil
1 c onion
2 large garlic cloves, minced
4 roma tomatoes
6 chopped tomatillos
1 chipotle chile
2 t adobo sauce
1 t oregano
1/2 t dried thyme
2 1/2 c packed shredded cooked chicken
1 c chicken broth
1 t salt
tostadas and toppings

Heat the oil over medium-high heat, add the onions and saute until softened, about 3 minutes.  Add the garlic, tomatoes, tomatillos, chile, adobo sauce, oregano, and thyme.  Reduce the heat and simmer, uncovered, for 10-15 minutes.  Add the chicken, broth, and salt, continue cooking for 20 or so minutes.  Serve with desired toppings.