1. Preheat oven to 425º. Season chicken on both sides with 3/4 teaspoon salt and 1/4 teaspoon pepper. In a large straight-sided skillet over medium-high heat, heat 1 tablespoon oil. Add chicken and cook, turning occasionally, until golden brown, 4 to 6 minutes per side. Transfer to a plate.

 

2. In same skillet over medium heat, heat remaining 1 tablespoon oil. Add onion and garlic and cook, stirring occasionally, until tender, 3 to 5 minutes. Add tomatoes and wine and cook, stirring and scraping up any brown bits on bottom of pan, until wine is mostly evaporated and tomatoes are just starting to wilt, about 2 minutes. Pour in broth and and cream and bring to a boil. Stir in gnocchi and nestle chicken back into pan.

 

3. Bake until chicken is cooked through and an instant-read thermometer inserted into thickest part registers 165°, 8 to 10 minutes. Transfer chicken to a cutting board.

 

4. Stir 2 tablespoons pesto into skillet. Top with mozzarella (if using). Continue to bake until pesto is warmed through and cheese is melted, about 4 minutes more. Let cool slightly.

 

5. Thinly slice chicken and return to skillet. Dollop top of bake with remaining 6 tablespoons pesto. Sprinkle with basil and pine nuts.