Preheat broiler. For sauce, mix sour cream and salsa.
In a large skillet coated with cooking spray, cook and stir red pepper and onion over medium heat until tender, 6-8 minutes. Add garlic; cook and stir 1 minute. Stir in broth, chickpeas, chipotles, cumin and salt; bring to a boil. Reduce heat; simmer, covered, 5 minutes.
Coarsely mash mixture with a potato masher; stir in cilantro and lime juice. If desired, cook over low heat to thicken, stirring frequently.
In batches, spritz both sides of tortillas with cooking spray and place on a baking sheet; broil 4-5 in. from heat until crisp and lightly browned, about 1 minute per side. To serve, top tortillas with chickpea mixture, lettuce, tomatoes, avocado and sauce. Sprinkle with cheese.
