In a large sauce pan, melt the butter over medium heat. Add the onions and saute until beginning to soften. Add the jalapenos and saute an additional 2-3 minutes. Add the ground beef to the pan and cook until no pink remains. Drain any excess fat then stir in taco seasoning.

Add the tomato sauce, kidney beans, and drained diced tomatoes to the skillet. Cook, stirring occasionally, until heated through.

To assemble, open Frito bags. Divide meat mixture evenly among the bags, filling about 2/3 full. Sprinkle with cheese. Add sour cream and lettuce if desired. Eat away!