See the Recipe Below!
Melt butter in a large pot on medium heat, add onion and saute until soft nut not browned, about 3-4 minutes. Add flour and saute another minute.
Add chicken broth, water, carrots, garlic, celery, brown rice and chicken thighs, cover and simmer 20 minutes. Add wild rice mix along with it's seasoning packet, long grain rice and mushrooms and simmer on low, covered 25 minutes, stirring occasionally.
Remove chicken from pot and shred with two forks, return to pot, add sour cream and more water if too thick, adjust salt and pepper to taste if needed and serve.