1. Cook pasta in a large pot of boiling salted water until tender but still firm, 5 to 7 minutes. Drain in a colander.
2. Meanwhile, season chicken with salt and pepper. In a large frying pan, heat half each of butter and olive oil over medium-high heat. Add chicken and cook, turning once, until white throughout, about 5 minutes. Remove from pan.
3. Add remaining butter and oil to pan, reduce heat to medium, and add scallions and garlic. Cook, stirring often, until garlic is softened, 2 to 3 minutes. Add broth, wine, basil, thyme, and hot pepper. Bring to a boil and cook, stirring occasionally, until sauce is reduced by about one-fourth, 5 to 7 minutes. Return chicken to pan to reheat briefly, then remove chicken again.
4. Toss pasta and 1/4 cup of parsley with sauce. Divide among plates. Arrange chicken on top and garnish with remaining parsley.