Fry hamburger and drain any fat drippings. While hamburger is cooking, chop green pepper, chop tomatoes, shred cheese and clean lettuce and tear into bite sized pieces. Cover the bottom of a 9X13 casserole dish with broken up nacho chips. Sprinkle with cooked drained hamburger. Cover with iceburg lettuce. Then layer with tomatoes and then green pepper. Top with cheddar cheese. Cook in a 350F oven for 10 minutes. Spoon onto plates and serve with your choice of salsa, sour cream and guacamole. Salsa and guacamole can be layered in the casserole itself, but I find people prefer to spoon them on top themselves.