Confetti Chicken and Veggies with Lemony Pasta

8 oz. dry campanelle or farfalle pasta, or your favorite2 T. butter2 bunches green onions, thinly sliced (keep white/green separate)1 T. minced garlic1 c. heavy cream¼ c. fresh lemon juice2 T. lemon zest2 c. shredded rotisserie chickenSalt/black pepper to taste3…