In 10-inch skillet, heat oil over medium-high heat. Cook chicken in oil about 3 minutes or until lightly browned. Add onion and bell pepper; cook 3 to 4 minutes until vegetables are crisp-tender.
Add cooking sauce. Reduce heat; simmer uncovered about 8 minutes or until chicken is no longer pink in center.
Spoon mixture on tortillas. Add toppings. Roll up tortillas.