Reserve 2 teaspoons of the taco seasoning mix in medium bowl. Coat chicken with remaining taco seasoning mix.
Heat oil in 12-inch skillet over medium heat. Cook chicken in oil 3 to 5 minutes, turning once, until brown. Reduce heat to medium-low. Cook about 8 minutes, turning once, until chicken is no longer pink when centers of thickest pieces are cut.
While chicken is cooking, add remaining ingredients to reserved taco seasoning mix; toss gently. Serve salsa with chicken.