In a large skillet, melt the butter and add the chicken. Cook, turning as needed for 10 minutes or until brown on both sides. Season with salt and pepper. Arrange chicken in single layer in a 9x13-inch glass baking dish.
Add mushrooms to the skillet and sauté 3 minutes. Scatter mushrooms over chicken and pour broth over all. Cover and bake for 15 minutes.
Melt remaining butter in skillet and sauté onion for 3 minutes. Add chilies, garlic and flour. Cook for 1 minute, stirring constantly.
Remove chicken from oven. Combine pan drippings and remaining broth in a measuring cup. Measure 1 cup and stir into onion mixture. Mix in yogurt and heat thoroughly. Spoon mixture over chicken. Sprinkle with cheese and return to oven.
4. Bake for 15 more minutes. To serve, sprinkle with pine nuts.
Notes
If you are preparing this recipe as GLUTEN-FREE, just be sure to use brands of chiles and chicken broth that are known to be GF, and use something else as a thickener to replace the flour: GF flour, cornstarch, or something else you prefer to use.