Heat olive oil in your largest pot over medium heat and season chicken breast with salt and pepper on both sides.
Sear chicken for about 3 minutes per side until golden but not cooked through; remove to a plate and set aside.
Add butter to the same pot and sauté the diced onion, carrots, and celery until the onion turns translucent, about 5 minutes.
Stir in minced garlic, hot sauce, and Worcestershire sauce for 30 seconds until fragrant.
Pour in the low sodium chicken broth and return the seared chicken to the pot along with the bay leaves.
Bring to a boil, reduce to a simmer, cover partially, and cook for about 20 minutes until the chicken shreds easily.
Remove chicken to a cutting board, shred with two forks, then return the shredded chicken to the pot with frozen mixed vegetables, dried parsley, dried basil, dried oregano, mustard powder, and black pepper.
Simmer uncovered for 15 minutes until vegetables are tender and flavors meld; remove bay leaves and adjust salt to taste.
Cool the soup at room temperature for 30 minutes before portioning into 5–6 airtight meal prep containers.
Label each container with the date using painter's tape and refrigerate promptly.