Cook the beef in a 10-inch skillet over medium-high heat until it's well browned, stirring often to separate meat. Pour off any fat.
Stir the picante sauce, chili powder, tomatoes and corn in the skillet and heat to a boil. Reduce the heat to low and cook for 10 minutes. Stir the pasta in the skillet and sprinkle with the cheese. Cover and heat until the cheese melts. Garnish with avocado and sour cream, if desired.