1.Cut Peppers In Half Lengthwise And Remove Seeds. Cook In Boiling Water For 5 Minutes; Drain And Set Aside. In A Large Skillet, Cook Beef And Onion Over Medium Heat Until Meat Is No Longer Pink; Drain. Add The Beans, Tomato Sauce And Taco Seasoning; Bring To A Boil. Reduce Heat; Simmer, Uncovered, For 5 Minutes. 2.Place Pepper Halves In An Ungreased 8-In. Square Baking Dish. Fill With Meat Mixture. Bake, Uncovered, At 350 Degrees F For 10 Minutes Or Until Peppers Are Tender. Top With Sour Cream, Cheese And Tomato.