Place the cooked beef, chopped onion, and all other ingredients in a large resealable freezer bag. Remove the excess air, seal, and freeze.
Optional: Top with shredded cheese, tortilla chips, chopped green onions, cilantro, and/or sliced avocado.
Heat on the stovetop on medium-low heat until heated through, stirring occasionally.
Optional: Top with shredded cheese, tortilla chips, chopped green onions, cilantro, and/or sliced avocado.