Set your instant pot to saute, brown onion and garlic for 2-3 minutes. add chicken continue to saute until cycle is complete
Set instant pot to pressure cook for 18 minutes. Add tomato sauce, then vegetable broth until chicken is covered. Add salt, oregano and cumin. lock lid and let cook.
Release pressure and strain liquid. Shred chicken with a fork. Add more salt to taste and serve. Enjoy!