Preheat the oven to 450 degrees F. Melt the butter with 2 tablespoons of vegetable oil in a skillet. Transfer to the bowl and set aside. Heat the remaining 2 tablespoons of oil in the skillet.
Add the onion, garlic, and jalapeno and cook until soft, about 3 minutes. Add the chili powder, cumin, cinnamon, and 1 teaspoon salt, cook for 30 seconds. Add the tomato and cilantro and cook until slightly dry, about 2 minutes. Stir in the chicken and sour cream and cook until warm and well blended. Remove from heat.
Brush a rimmed baking sheet with some of the butter-oil mixtures. Spread 2 tablespoons of refried beans down the center of each tortilla,
leaving a 2-inch border on both ends. Top with 1 cup chicken mixture and ¼ cup of cheese. Fold in the ends and roll up.
Put the chimichangas seam-side down on the baking sheet brush with the butter-oil mixture. Bake for 8 to 10 minutes per side, brushing again after you flip. Remove from the oven.
Top with the sauce (sauce recipe below), more cheese, lettuce, and tomato.
While the chimichangas are baking sauté ½ cup chopped onion, 2 garlic cloves in a skillet with vegetable oil. Add in a pinch of chili powder, cumin, sugar, and salt. Cook 30 seconds.
Stir in two (4-ounce) cans chopped green chiles, (drained and rinsed); cook for 2 minutes. Add 1 cup chicken broth and simmer until thickened, then puree in a blender. Stir in ¼ cup of chopped cilantro.