Question: how long to cook a chicken breast at 375 degrees?
Answer: Preheat oven to 375 degrees. Place chicken breasts in a 9-by-13-inch baking dish. Season both sides generously with salt and pepper. ... 
Bake until a meat thermometer registers 160 degrees in the thickest part of the breast, about 20 minutes. Remove chicken from pan; let rest 10 minutes before slicing.