In a medium saucepan over medium heat, heat the olive oil and sauté the garlic for about 1-2 minutes, until fragrant. Add the chipotle peppers, adobo sauce, tomato sauce, oregano, chili powder, cumin, broth, salt, and pepper. Bring to a boil. Then, lower the heat and simmer for 5-10 minutes to thicken the sauce. Set aside.