Scatter chopped onion and butter pieces into the bottom of a 9x13-inch baking dish. Place bread crumbs into a shallow bowl; press chicken breast halves into crumbs to coat. Place coated chicken breasts atop onion and butter.
Bake in the preheated oven until crumbs are browned and chicken juices run clear, about 40 minutes.
Mix red wine, chili sauce, and currant jelly in a bowl; pour sauce over chicken. Bake until sauce thickens and glazes onto chicken breasts, about 30 more minutes.