4 ounces chopped walnuts
in a large bowl, using an electric mixer, beat butter and sugar on medium-high until fluffy, 3 minutes. Add eggs, one at a time, beating well after each addition and scraping the sides of the bowl. Beat in bananas, sour cream or yogurt, and vanilla. Beat in flour mixture and chocolate on medium. Pour batter into your pan. Bake until a skewer inserted in the center of the loaf comes out clean, 50 to 60 minutes.
Let bread cool in pan 10 minutes. Remove bread from pan and let cool completely.