Place a large pot over medium-high heat. Drizzle the bottom with avocado oil. Put the brown rice flour in a bowl and season with salt and pepper. Dredge chicken thighs in brown rice flour and place them in a hot pan.
Brown the chicken on both sides for about two to three minutes per side.
Remove the chicken from the pot and place it on a clean plate.
Add the garlic to the pot and sauté for a few minutes until soft and fragrant. Then add the celery, onion, and carrot, and sauté the mixture until the vegetables are tender for about two to three minutes. Season with salt and pepper. Add the tomatoes and bring the mixture to a simmer.
Add the orzo pasta to the tomatoes, then add the chicken back in and bring to a boil. Pour the water, cover, and reduce the heat to medium-low. Let the mixture simmer for about 20 to 25 minutes until the chicken is fully cooked or reads an internal temperature of 165.
Remove lid. Taste your sauce, then add additional seasoning if needed. Serve and enjoy.
