I made this for our Cinco de Mayo dinner this year. I have another Mexican Lasagna recipe and decided that I would make this one a lasagna instead of using tortillas. I switched the recipe up some by adding poblanos (my favorite pepper) and roasting the vegetables. The original recipe didn't do that. I actually added 3 jalapenos, but since I didn't take the seeds out entirely, it was a little too hot for me, but others really liked it hot. I will make it again!
Preheat oven to 400 degrees. Prepare tomatillos and onion, and place on a large sheet pan. Add the whole jalapenos and poblano(s). (If you like extra spice, add another jalapeno.) Roast these vegetables for about 15 minutes, until tender.
Remove the vegetables from the oven and place in a food processor or blender and puree, add salt to taste. If using the blender, you will need to do in batches. Be careful when blending hot foods or liquids, don't fill too full.
In a medium bowl combine shredded cheese, cream cheese, and chili powder. I used a mixer. (The picture here is the vegies pureed.)
Coat a 3-quart rectangular baking dish with cooking spray. Spoon one-fourth of the tomatillo mixture into the prepared baking dish. Lay down lasagna noodles to cover. Top with 1/3 of the chicken and 1/3 of the cheese mixture and then 1/4 of the tomatillo sauce. Repeat 2 more times, ending with the tomatillo sauce. Cover with foil.
Bake about 30 minutes or until heated through and bubbly around the edges.
NOTE: I made this a day ahead and kept in the refrigerator. Then took it out an hour before and brought to room temperature. It takes closer to an hour to bake when doing this since none of the ingredients are hot at the time it goes in the oven.