Chicken: In a medium pot of boiling water, cook the chicken until it looses its pink color; about 20-25 minutes. During this time, you can prep other ingredients.
Shred: In a food processor, shred the chicken to a fine texture.
Mix: To a large bowl, add the chicken, cheese, diced onion, garlic, pepper and garlic salt and mix until well combined. Set aside.
Set temperature: Preheat the oven to 375° F.
Tortillas: Lightly spray both sides of the corn tortillas with some olive oil cooking spray and add to a baking sheet. Bake for 2-3 minutes to soften the tortillas. (Don’t skip this step. This will prevent the tortillas from cracking and splitting when you go to fill them with the chicken mixture).
Temperature increase: Increase the oven temperature to 400° F.
Sauce: Pour just enough enchilada sauce on the bottom of a 13 by 9 inch pan to coat. (This will keep your enchiladas from sticking).
Assemble: Fill each tortilla with 1 1/2 to 2 big spoonfuls of the chicken mixture. (I gently pack down each spoonful a little bit so it’s easier to work with). As you roll it, pack the mixture and tuck the tortillas as you go.
Add to the pan: Lay 6 enchiladas in a row, and two in the middle.
Bake: Top with additional cheese and bake for 15-20 minutes, or until the cheese is melted and the enchiladas are warmed through.