Chicken and Wild Rice Casserole

I'm always looking for a filling recipe, and when I saw this on pinterest via RachelSchultz-I was intrigued.  I halved the original recipe, but it went a long way, and it lasted long beyond the last bite.  The cheese gives it a great flavor, and the rice stuck with me, which was a great combo!
So the next time you are hungry (and I'm speaking to future me... in third person, annoying), pull this out of the recipe vault....
Chicken and Wild Rice Casserole
Ingredients:  3 T olive oil, 1 white onion (diced), 3 stalks celery (diced), 3 carrots (diced), 2 T garlic (minced), 2 c chicken breast (cooked and shredded), 1 c. white rice, 16 oz wild rice, 3 T butter, 1/4 c. whole wheat flour, 1 c. vegetable broth, 4 c. cheddar cheese (shredded), garlic salt, salt and pepper.
Instructions:  Cook both rices according to packaged instructions.  Cook and shred the chicken.  Heat oil, onion, celery, garlic, and carrots in a pan over med heat for 10 minutes.  Stir in chicken, rices, and a dash of salt pepper, and garlic salt.  Reduce heat to low.  In a second pan over med/high, melt the butter.  Whisk in flour, vegetable broth (I used chicken), and salt and pepper to taste.  Continue to whisk until boiling.  Add 2 c. shredded cheddar cheese and stir until melted.  Place chicken and rice mix into a greased 9x13 pan.  Pour cheese sauce over rices and top with remaining cheddar.  Bake for 30 minutes at 350.