1. Cook beef in a large nonstick skillet over medium-high heat until browned, stirring to crumble. Drain well; return beef to pan. Add tomato paste and next 4 ingredients (through diced tomatoes), and bring to a boil. Reduce heat, and simmer 5 minutes or until thick, stirring occasionally.
2. Spoon meat mixture into a serving bowl; top with crumbled cheese and green onions. Serve with tortilla chips.