Heat the olive oil and butter in a large Dutch oven or heavy pot over medium-high heat.
Season the chicken with paprika, garlic powder, salt, and black pepper.
Add the chicken and cook for 4 to 5 minutes until lightly browned. Remove from the pot and set aside.
Add the onion and carrots to the pot and cook for about 5 minutes until softened.
Stir in the garlic and cook for 30 seconds until fragrant.
Mix in the tomato paste and cook for 1 minute.
Pour in the chicken broth and Worcestershire sauce, scraping up any browned bits from the bottom of the pot.
Add the Italian seasoning, thyme, baby potatoes, and browned chicken.
Bring the stew to a gentle boil.
Reduce the heat to low, cover, and simmer for 30 to 35 minutes until the potatoes are tender and the chicken is fully cooked.
If you prefer a thicker stew, whisk together the cornstarch and cold water, then stir it into the stew. Simmer for another 2 to 3 minutes until thickened.
Taste and adjust the seasoning if needed.
Sprinkle with fresh parsley before serving.