Heat olive oil in a large skillet over medium heat.
Add diced chicken, then season with salt, black pepper, garlic powder, and onion powder.
Cook chicken for 5–7 minutes until browned and fully cooked, then remove from skillet and set aside.
Add rice, chicken broth, and milk to the same skillet; stir and bring to a boil.
Reduce heat to low, cover the skillet, and simmer for 18–20 minutes until rice is tender.
Return cooked chicken to the skillet and stir in shredded cheddar cheese until melted and creamy.
Add optional vegetables such as peas, corn, bell peppers, or green onions if desired.
Let the skillet sit for a few minutes to thicken before serving warm.