I roast 4 boneless, skinless chicken breasts for this recipe. Season the chicken with pepper, garlic powder and seasoned salt before roasting. I use my grill and place them on my rotiserie, keeping the temperature between 250-300 until juices run clear. Let the chicken cool, and use a fork or other utinsel to shred the chicken. Of coarse, any store bought already roasted chicken will do just fine.
Brush tomatillos and garlic with 1 tbsp olive oil.
Roast Tomatillos on the grill, until slightly charred. Once they pop and release water, remove.
Cut the top of the garlic to expose cloves and drizzle with olive oil, wrap in foil and roast on the grill or oven (on a baking sheet) for 10-20 minutes turning often. until slightly charred. Peel the garlic simply by squeezing the clove, the garlic should "slide" right out of the peel.
In a large pot, saute onions in in olive oil over medium heat until semi soft (about 5 to 8 minutes) stirring often.
Stir in the chiles, tomatillos, garlic, broth and the 2 corn tortillias that were sliced.
Bring to a boil and reduce heat to simmer. simmer for 10 minutes, stirring often. Remove from heat.
stir in cilantro and salt.
In small batches, place in food processor or blender and pulse until sauce is smooth, but still a bit chunky.
stir in sour cream.
Stir in shredded chicken.
In a 13x9 baking dish, place just enough mixture to cover the bottom, add enough cheese to cover the sauce and then a layer tortillas on top of the mixture, repeat. Top your creation with the remaining mixture and the remaining cheese.
Bake at 350 degrees for 25-30 minutes until cheese begins to slightly brown.