Step 1: Prepare chicken
Place chicken breasts in a large zip top bag and seal. Use a mallet or meat tenderizer to pound the breasts into cutlets about 1/2-inch thick. Remove cutlets from bag and sprinkle each generously with 1 Tbsp. of seasoning to coat.
Step 2: Cook and shred chicken
Heat oil in a large skillet over medium-high heat. Add chicken cutlets and cook for 3 to 4 min. per side, or until cooked through and slightly charred. Cover skillet to keep oil from splattering. Transfer chicken to a plate and cover with foil for at least 5 min. to rest. Use two forks to shred the chicken into pieces and transfer it to a serving bowl. Meanwhile, throw the carrots into the same skillet you used to cook the chicken (without cleaning it out) and cook over medium-high for about 5 min. or until barely tender and slightly browned. Transfer carrots to a serving bowl.
Step 3: Finish and serve
When ready to serve tacos, heat the tortillas: wrap in damp paper towel and microwave for 30 seconds, toast in a dry skillet 30 seconds per side, or set over a gas stove flame for a few seconds per side.