In a small bowl, mix together the cumin, chili powder, garlic powder and oregano.
Sprinkle the seasonings over the top of the chicken breasts.
Pour salsa and diced tomatoes over the top of the chicken.
Place the lid on your slow cooker. Cook on low for 5 hours, or on high for 2.5 hours. I recommend cooking on low heat if you have the time.
Use an instant read thermometer to check the internal temperature of the chicken. When it’s at least 165 degrees Fahrenheit and shreds easily, it’s done.
Use tongs to transfer chicken into a large bowl. Shred chicken with two forks or a hand mixer.
After the chicken is shredded, return it to the crockpot. Using tongs, toss the shredded chicken with the sauce until evenly coated.
Allow the shredded chicken to rest in the salsa mixture on low heat, uncovered, for 15-20 minutes before serving.
