Prepare chicken strips according to stove-top package directions. Remove chicken from skillet.
Sauté onion, bell pepper, and next 3 ingredients in hot oil in skillet over medium-high heat 6 to 8 minutes or until vegetables are lightly browned. Stir in chicken strips and 2 Tbsp. water, and cook 2 to 3 minutes or until mixture is thoroughly heated.
Arrange tortillas in 4 individual serving bowls. Divide lettuce and cheese evenly in tortilla-lined bowls. Top with hot chicken mixture. Serve with desired toppings.