Note: I served this dish with brown rice. If that's what you choose I recommend starting the chicken and rice at the same time as they both take ~40 minutes to cook. Another alternative to cooking it separately is to bake the dish with the rice - add extra salsa for moisture.
Combine avocado, tomato, garlic, vinegar and lime juice in small bowl. Season to taste (~1/8 tsp cumin, dash of salt, dash of pepper).
Slice chicken lengthwise, leaving some in-tact at the ends (like a pita), or slice in half lengthwise and tenderize.
Stuff liberally with guacamole, or wrap tenderized chicken around guacamole and hold with a toothpick.
Place chicken in glass baking dish, cover with salsa.
Scatter cheese on top (If you prefer melted cheese instead of crispy, add 10 minutes before removing chicken from the oven).
Bake at 450 F for 40 - 45 minutes, or until chicken is fully cooked. Chicken should cool slightly before being served.