Sauté Aromatics: In a large pot over medium heat, heat 1 teaspoon avocado oil and cook ½ cup diced onion for about 4 minutes, until soft and translucent. Add 2 garlic cloves (minced) and stir for 1 additional minute.
Add Base: Pour in 32 ounces low-sodium chicken stock, 2 (15-ounce) cans Northern beans (drained and rinsed), 1 (14.5-ounce) can low-sodium diced tomatoes, 1 (14.5-ounce) can crushed tomatoes, 12-16 ounces frozen vegetables, 1 tablespoon dried parsley, 1 teaspoon garlic powder, 1 teaspoon onion powder, 1 teaspoon dried rosemary, 1 teaspoon dried thyme, 1 teaspoon coarse Kosher salt, and ½ teaspoon black pepper. Stir everything together. Hold off on adding the chicken for now.
Simmer: Bring soup to a gentle boil, then lower heat and let simmer for 15 minutes so the flavors can come together.
Add Chicken: Stir in 1 pound cooked shredded chicken and let soup simmer a few more minutes until chicken is heated through.
Serve: Taste and adjust seasoning, if needed, then ladle into bowls and serve.