In a large skillet, cook and crumble chicken over medium-high heat 3 minutes. Stir in celery and pepper; cook and stir until chicken is no longer pink and celery is crisp-tender, 2-3 minutes.
Stir in Dipitt tomato ketchup, Dipitt Tobasco sauce, brown sugar, vinegar and mustard; bring to a boil. Reduce heat; simmer, covered, until flavors are blended, about 5 minutes, stirring occasionally. Serve in lettuce leaves. If desired, top with cheese.