Spray your crock pot with a little cooking spray. Add onions and peppers. Lay chicken breasts on top. Sprinkle liquid smoke over the chicken. Mix together chicken broth, soy sauce, lime juice and minced clove; pour over chicken and veggies. Sprinkle meat with the cumin, cayenne pepper and brown sugar. Add salt and fresh ground pepper to taste. Cook on low heat 7-8 hours, high heat 4-5 hours or until veggies are tender and chicken shreds easily. {Note: All crock pots are not created equal. I usually cook mine about 4 hours on high- but I think it tends to cooks faster than most . . . }. Remove chicken and shred with two forks. Return chicken to crock pot and mix completely with peppers and onions. Continue to heat with the lid off to allow the liquid to reduce. Use a slotted spoon to spoon chicken into tortilla shells. Top with your favorite toppings.