Preheat oven to 400°F. Then, pour 2 cups of Enchilada sauce (use all the sauce if using above recipe) along with the remaining chopped garlic in a medium sized sauce pan. Heat sauce on medium heat until it start bubbling.
Nestle the sesasoned chicken breast in the sauce and make sure its sunk in the sauce. Cook on low heat covered for 20-30 minutes until chicken is cooked.
Seperate the chicken from the sauce and shred with two forks and let sauce cool. Add it to a medium sized bowl. Next add the shredded cheese, cilantro and half of the sauce the chicken cooked in.
Toss it all up and warm up tortillas in a wet paper towel for 30 seconds. This will help the tortillas from not tearing up.
Create an assembly line. Starting with tortillas, chicken filling, enchilada sauce and a greased 9x13 baking casserole dish.
Pour 2 tablespoons of sauce in the baking dish. Lay a tortilla in the baking pan and add 2 tablespoons of chicken filling, a teaspoon of enchilada sauce and gently roll. Lay seam side down. Repeat with all remaining tortillas.
Spoon remaining enchilada sauce over the enchiladas, add cheese, onions, cilantro and jalapeno slices.
Bake for 10-12 minutes until cheese is melted and tortillas have turned golden.