Kale Pesto Chicken Pasta

In a large pot of salted boiling water, cook pasta according to package directions until al dente. Drain and return to pot. In a grill pan (or a large skillet), heat olive oil over medium-high heat. Season both sides of chicken with salt and pepper then add to skillet. Cook until golden and seared on both sides, about 8 minutes per side. Let rest for 10 minutes, then slice into 1/2" pieces. Make pesto: Combine kale, basil, and walnuts in a food processor. Pulse until greens and nuts are finely chopped. Scrape down the sides, then add olive oil, Parmesan, garlic, and lemon juice and season with salt. Pulse until blended. Pour pesto over pasta, then add tomatoes and mozzarella and toss until combined. Top with sliced chicken. Serve with more basil and Parmesan.