Spray crockpot with cooking spray. Lay down layer of tortillas. Each crockpot will vary in size. Mine took 4 small tortillas to cover the bottom.
Next, spread a layer of tomatoes.
Sprinkle some chopped onions on top of the tomatoes.
Next spread a layer of black beans.
Cover beans with a layer of salsa.
Apply a generous amount of fajita seasoning.
Next layer on your chicken.
Cover chicken with a layer of corn.
Top corn with a layer of shredded cheese.
Like I said, all crockpots are different shapes and sizes. So keep layering until you are a couple inches from the top. I was able to repeat the layers 3 times. When you do reach the top, for the final layer, do a later of tortillas, topped with the rest of your tomatoes and cheese.
Cook on low for 3-4 hours or on high for 2 hours. Top with sour cream of avocado :)
Recipe by Family Fresh Meals at http://www.familyfreshmeals.com/2011/10/crockpot-mexican-lasagna-stack-up.html