Stir together avocado and jicama with lime juice in small bowl; set aside.
Heat oil in large skillet over medium-high heat. Add chicken strips; cook and stir 4 to 6 minutes or until chicken is no longer pink. Stir in taco seasoning mix and water. Bring to a boil. Reduce heat to low; cook for 2 to 3 minutes or until mixture thickens, stirring occasionally. Remove from heat.
Crush taco shells, then microwave on HIGH (100%) 1 minute.
Spoon chicken filling onto each lettuce leaf; layer with taco shells, avocado mixture, cheese and cilantro. Wrap lettuce around filling and serve with taco sauce.