In a sauce pan over medium high heat, add chicken ingredients. Let cook for 20 minutes. Remove chicken from pan and shred.
In another sauce pan over medium heat, add rice ingredients. Cover and let cook for 17 minutes. Remove from heat, without removing lid until ready to build burritos.
In a small sauce pan over medium low heat, add black beans ingredients. Let cook while chicken and rice are cooking. Stir occasionally and smash slightly.
In a bowl, add avocado, lime juice, salt, pepper and cumin. Use a fork to slightly smash together. (Smash to your desired consistency, but I suggest leaving some chunks).
Preheat large frying pan or griddle to medium high.
To build the burrito, place tortilla on a flat surface and sprinkle ⅓ cup cheese evenly. Then add portion of chicken, rice, corn salsa, black beans, sour cream and smashed avocado. Fold in sides of tortilla and then roll up from the bottom to top, tucking tortilla as needed. Repeat with remaining burritos.
Place burrito, seam side down, in hot pan/griddle. Let cook for 2 minutes (until slightly golden), then flip and cook another 2 minutes. Remove from heat and repeat with remaining burritos.