In a large plastic ziplock bag, add spices. Shake to mix.
Put chicken breasts in plastic bag and roll to coat them in spices.
Grill chicken until cooked completely through. (Time will depend on how thick the chicken is and how hot the grill is.)
While chicken cooks, heat a large sauce pan over medium heat. Add olive oil and peppers and onions. Cook for 5-7 minutes until they begin to soften a little.
Slice the chicken when it's cooked. Put chicken, peppers and onions in a large bowl.
Squeeze lime juice on top and stir to combine.
Serve on tortillas and top with any optional toppings.
Optional toppings: shredded cheese, guacamole, sour cream, salsa, hot sauce, chopped fresh cilantro, lime juice.