1. Heat the olive oil in a large skillet over medium heat. Season the chicken on both sides with oregano, salt, and black pepper.

2. Add the chicken to the skillet and cook for about 8 minutes per side, or until golden brown and cooked through to 165°F. Transfer the chicken to a plate.

3. In the same skillet, melt the butter over medium heat. Add the garlic and cook for about 1 minute, stirring often, until fragrant.

4. Add the cherry tomatoes and season lightly with salt and black pepper. Cook for about 5 minutes, stirring occasionally, until the tomatoes soften and begin to release their juices.

5. Stir in the baby spinach and cook for 2 to 3 minutes, until just wilted.

6. Pour in the heavy cream and add the Parmesan cheese. Stir well and bring the sauce to a gentle simmer. Reduce the heat to low and cook for about 3 minutes, until slightly thickened.

7. Return the chicken to the skillet and spoon the sauce over the top. Cook for 5 to 7 minutes, until the chicken is warmed through.

8. Serve the chicken with the creamy tomato-spinach sauce and lemon wedges on the side.