In a large bowl, combine the shredded chicken, black beans, corn, diced tomatoes, and taco seasoning.
Mix thoroughly until well combined.
Lay out a tortilla on a flat surface.
Place a portion of the chicken mixture in the center of the tortilla.
Top with shredded cheese, lettuce, and mashed avocado.
Fold in the sides of the tortilla and roll it tightly from the bottom up.
Repeat with the remaining tortillas and filling.
In a skillet over medium heat, place the burritos seam-side down.
Cook for about 3-4 minutes until golden brown, then flip and cook the other side.
Remove from heat and let rest for a minute before slicing in half.