Preheat your oven to 375 degrees F.

In a small pot or large sauce pan, place chicken stock, onion, garlic, cilantro, peppercorns, cumin, chili powder, coriander and oregano and bring to a boil. Cover and lower to a simmer and cook five minutes.

Remove lid, add uncooked chicken breasts, cover and remove from heat. The chicken will sit in the hot liquid for five minutes off heat.

Pour mixture through strainer and save liquid. Pick out chicken pieces and lay out to cool on a plate or platter. Discard the remaining solids. (NOTE: The chicken will not be fully cooked after this step. It will finish cooking later in the process.)

If you want your chicken shredded, shred now with two forks, or leave in pieces.

In a large nonstick 3-4 quart pan, melt butter in oil over medium heat and once melted, add both bell peppers, jalapeno and onion and saute three minutes. Add garlic and cook one more minute.

Lower the heat to medium-low and add the flour and stir. Cook for two minutes, increase heat to medium high and add the stock reserved from earlier.

Stir to form a sauce then add the drained tomatoes, cut up corn tortillas and the cooked chicken from earlier. Stir to combine then remove from the heat.

Spray a 9x9x3-inch casserole dish with kitchen pan spray and pour in the mixture.

Top with the Jack cheese and bake for 15 minutes or until hot and bubbly.

Place under the broiler for a minute or two to brown slightly.

Let sit for ten minutes to set up and then serve with chopped fresh cilantro over the tops of portions.