Heat olive oil in a large skillet over medium-high heat.
Season the chicken pieces with salt, black pepper, garlic powder, and onion powder.
Add the chicken to the skillet and cook for 5-6 minutes, stirring occasionally, until browned and cooked through. Remove chicken from the skillet and set aside.
In the same skillet, add the minced garlic and cook for 30 seconds until fragrant.
Add the orzo pasta to the skillet and stir to coat with the oil and garlic.
Pour in the chicken broth and milk, then add the dried thyme and crushed red pepper flakes if using.
Bring the mixture to a boil, then reduce heat to medium-low and simmer uncovered for 8 minutes, stirring occasionally.
Add the chopped broccoli florets to the skillet, stir to combine, and cook for an additional 5-7 minutes until the orzo is tender and the broccoli is bright green and crisp-tender.
Return the cooked chicken to the skillet and stir in the shredded cheddar cheese and grated Parmesan cheese until melted and creamy.
Remove from heat and let the dish rest for 2 minutes before serving.