Coat chicken with salt and pepper then place them in the bottom of a large saucepan. Cover the chicken with water and bring to a boil. As soon as the water starts boiling, reduce to a simmer, cover chicken with a lid and simmer for 15-20 minutes.
Meanwhile, make the chipotle sauce by adding the chipotle pepper, sauce and lime juice to a blender or food processor and pulsing until smooth.
Next, heat the tortillas over skillet, cook the corn and dice the tomatoes.
Once the chicken is cooked, use two forks to shred the chicken, then place it in a large bowl and pour the chipotle sauce over top, using kitchen tongs to stir everything together.
Last, assemble the tacos by adding the chicken to the tortillas, then the tomatoes, corn, lettuce, cheese, and avocado.
*You can also use regular canned tomatoes and broil them yourself in your broiler, if you prefer.