Heat the olive oil in a large skillet over medium heat.
Add the chicken breasts to the skillet and season them with salt and pepper.
Remove the chicken from the skillet and set it aside.
In the same skillet, add diced onion and sauté for 3–4 minutes until translucent.
Add the minced garlic and cook for an additional minute until fragrant.
Stir in the diced tomatoes and Italian seasoning, allowing them to meld for a few minutes.
Pour in the heavy cream and stir well to combine.
Return the chicken to the skillet, coating it with the sauce.
Stir in the fresh basil and cook for an additional minute.
Adjust seasoning with salt and pepper if needed, then serve hot.