In medium saucepan, heat oil over medium heat. Add onion and garlic and cook 4 minutes or until onions are softened, stirring frequently. Add beans with their liquid, the chipotle, and oregano. Bring to a boil over medium heat.
Preheat oven to 350 degrees. Break taco shells into large chips and arrange in an even layer on a large baking sheet. Bake 8 minutes or until heated through.
Arrange warm chips on large serving platter. Sprinkle evenly with cheese then pour bean mixture over chips. Top with salsa and sour cream and sprinkle with diced green chiles. Serve immediately.