In a large skillet, heat olive oil over medium-high heat. Add chicken, salt and pepper; cook until browned on all sides and cooked through. Remove to a bowl and set aside.
Reduce heat to medium and add onions. Cook, stirring, until softened and translucent, about 5 minutes. Add mushrooms and continue cooking until mushrooms are cooked. Add chicken back in along with garlic. Cook for 1 minute or until fragrant.
Reduce heat to medium-low and add cream cheese, cheddar cheese, and milk. Continue to cook over low heat until cheese has melted and a creamy sauce has formed. Add more milk if desired to thin sauce. Season to taste.
Serve over cooked brown rice, and garnish with fresh parsley.
Notes
Nutrition information does not include rice or parsley.
If desired, substitute boneless skinless chicken breasts.
Brown rice is more nutritious but if you prefer, substitute long grain white rice or jasmine rice. Quinoa or couscous are good substitutes, as well.