Saute chopped onion in a small bit of oil until translucent.
Add ground meat and cook until no pink remains. Drain meat and sprinkle taco seasoning, blending together.
Place drained meat and all remaining ingredients into slow cooker. Turn cooker on low and warm through.
Serve soup in bowls. Top with garnish if desired: sprinkling of shredded cheese, dollop of sour cream, chopped chives or slice of jalapeno.