Season chicken breasts with salt and pepper. Place in a large saucepan and cover completely with cold water. Bring to a boil over high heat, then maintain a steady boil and cook for 20 minutes, or until the internal temperature reaches 165 degrees F with no pink inside. Cook time may range from 15 to 25 minutes depending on size.

While the chicken boils, add the tomato sauce, mayonnaise, chipotle peppers in adobo, lime juice, garlic, cumin, and salt to a small blender or food processor. Blend until completely smooth, about 30 to 60 seconds. Taste and adjust salt or lime if needed.

Heat or cook the corn in a small skillet over medium heat for 2 to 3 minutes until warmed through. Chop the cilantro, slice the avocados, and warm your tortillas. For a gas stove, carefully char each tortilla directly over the flame for 15 to 20 seconds per side.

Transfer the cooked chicken to a cutting board. Use two forks to shred it into strips. If any pink remains, return the chicken to the hot water for 5 more minutes before shredding.

Add the shredded chicken to a large skillet over medium heat. Pour the chipotle sauce over the chicken and stir to coat every piece. Cook for 2 to 3 minutes, stirring occasionally, until the sauce is warm and the chicken is fully coated.

Assemble the tacos by adding chipotle chicken to each tortilla, then top with corn, sliced avocado, chopped cilantro, and cotija cheese. Serve immediately.