Enchiladas de Pollo y Queso

5 T butter
1 cup chopped onion
2 cups cooked chicken, chopped or shredded
4 oz chopped green chilies
1/4 cup flour
1 T chili powder
1/2 tsp ground coriander
1/2 tsp. ground cumin
2 1/2 cups chicken broth
1 cup sour cream
1 1/2 cups shredded Monterey Jack
12 tortillas-I prefer flour
Melt 2 T. butter and cook onions until softened. Remove to a bowl. Add chicken and green chilies. Melt remaining butter. Blend in flour and seasonings. Whisk in chicken broth. Cook, stirring until sauce boils. Remove from heat. Stir in sour cream and ? cup cheese. Stir ? cup sauce into chicken mixture. Spoon chicken mixture into tortillas and roll up. Place in 9x13 pan. Top with remaining sauce and cheese. Bake uncovered at 350 for about 25 minutes.