Heat olive oil in a large skillet over medium heat. Season the chicken thighs with smoked paprika, garlic powder, salt, and pepper.
Add the chicken thighs to the skillet and cook for about 6-7 minutes on each side, or until the chicken is golden brown and cooked through. Remove from skillet and set aside.
In the same skillet, add the diced red bell pepper and chopped red onion. Sauté for about 4-5 minutes, or until softened.
Stir in the minced garlic and cherry tomatoes and cook for another 2 minutes until the tomatoes begin to soften.
Add the Kalamata olives and baby spinach to the skillet, stirring until the spinach wilts down.
Return the cooked chicken to the skillet and pour in the lemon juice and fresh oregano. Let it simmer for another 2-3 minutes to heat through.
Taste and adjust seasoning if necessary, adding more salt and pepper as desired.