Preheat oven to 400 degrees F. Spray a 3 qt. baking dish (like a 9x13 pan) with nonstick spray and set aside.
Add butter to a deep pot (I like to use my enameled dutch oven), over MED heat. Add onions and cook until softened and fragrant, about 3 minutes. Add garlic and cook about a minute more, stirring frequently.
Add flour, cumin, oregano, cayenne and salt and pepper to taste and stir to combine. Slowly pour in chicken stock and cream, stirring as you pour, until combined. Bring to a simmer and cook until slightly thickened (enough that it coats the back of a wooden spoon).
Add 1 cup of the cheese to the cream sauce, stirring in until melted. Remove from heat and add shredded chicken, white beans, green chiles, salsa verde and cilantro and stir to combine.
Add a handful of the crushed tortilla chips to the bottom of prepared baking dish, enough to loosely cover it. Top with 1/3 of the chicken mixture, more crushed tortilla chips and 1/3 of the remaining cheese.
Repeat with another 1/3 of the chicken mixture, more tortilla chips and 1/2 of the remaining cheese. Top with last bit of the chicken mixture, the last bit of the tortilla chips and remaining cheese.
Spray some aluminum foil with nonstick spray and cover the baking dish (sprayed side down), and bake for 30 minutes. Remove foil and bake another 8-10 minutes until bubbly and golden brown.
Garnish with cilantro and serve hot.