Combine the chicken breast, broth, and dry seasonings in a 6qt or larger Crock Pot. Mix well to coat the chicken in the seasonings.
2 lbs raw chicken breast, ¾ cup chicken broth, 1 teaspoon kosher salt, ½ teaspoon black pepper, 1 ¼ teaspoon garlic powder, 1 ¼ teaspoon onion powder, 1 tablespoon Italian seasoning
Cook on low for 3-4 hours or high for 2-3 hours, until the chicken easily shreds when prodded with a fork.
Remove the chicken and shred on a cutting board by using two forks to pull it apart. Discard the cooking liquids. Put the shredded chicken back into the empty crock pot and allow it to release steam for 5 minutes before proceeding to the next step.
While the chicken is cooling, heat the marinara sauce until warm in the microwave or on the stove (I do this right in the jar without a lid in the microwave). Toss the chicken with the warm sauce, mozzarella, parmesan, and basil until well combined.
1 (22oz) jar marinara sauce, 1 ½ cups mozzarella cheese, ½ cup parmesan cheese, 1 tablespoon fresh basil
Spread the buns with oil or butter, then toast under the broiler or in a dry skillet on the stove. Assemble the sandwiches and serve.
6 brioche hamburger buns, Oil or softened butter