Preheat your oven to 400°F.
Toss the halved Roma tomatoes, yellow onion, and garlic cloves with olive oil, sea salt, and black pepper on a large rimmed baking sheet.
Place the chicken breast on a separate small baking tray and roast both trays for 25 to 30 minutes until the chicken is cooked through and the tomatoes are slightly charred.
Remove from the oven and use two forks to shred the chicken breast into bite-sized pieces, then set aside.
Transfer the roasted tomatoes, onion, garlic, and any accumulated juices into a high-speed blender.
Add the chicken bone broth, nutritional yeast, and fresh basil to the blender and process until the soup is completely smooth and creamy.
Pour the blended soup into a medium pot over medium heat, stir in the shredded chicken, and simmer for 2 minutes before serving hot.