Gather all your ingredients. Chop the tomatoes and dice the avocado. Set them aside for later use.
In a mixing bowl, combine the salsa, ground cumin, and chili powder. Place the chicken breasts in the slow cooker and pour the salsa mixture over the top, ensuring the chicken is well coated.
Add the corn kernels and black beans to the slow cooker. Pour in the low-sodium chicken broth, which will keep everything moist and flavorful during the cooking process.
Cover the slow cooker and set it on low for 6-8 hours or high for 3-4 hours.
Once the chicken is cooked through and tender, remove it from the slow cooker and use tongs to shred it into bite-sized pieces. Return the shredded chicken to the slow cooker and mix it well with the other ingredients.
Warm the whole-wheat tortillas in a dry skillet over medium heat for about 30 seconds on each side or until pliable.
To serve, take a warm tortilla and fill it with the shredded chicken mixture. Top it with shredded romaine lettuce, diced tomatoes, cheddar cheese, diced avocado, and a dollop of Greek yogurt for a creamy finish.
