Heat 2 Tbsp. olive oil in a large skillet over medium heat. Add bell pepper and next 3 ingredients. Cook 8 minutes or until pepper and onion are tender, stirring often. Add chicken, cilantro, and jalapeño peppers; cook 2 minutes or until thoroughly heated. Remove from heat, and keep warm.
Warm tortillas according to package directions.
Transfer chicken mixture to a serving platter. Serve with tortillas and desired toppings.