01 -
Season chicken breasts evenly with Italian seasoning, kosher salt, and garlic powder. Place chicken in the slow cooker.
02 -
Pour marinara sauce over the chicken breasts, ensuring thorough coverage. Set the slow cooker to low for 7–8 hours or high for 3–4 hours, until the chicken is fork-tender.
03 -
Once tender, transfer chicken to a cutting board and shred using two forks. Return shredded chicken to the slow cooker. Add grated parmesan cheese and stir until well combined.
04 -
Preheat broiler. Lightly toast the hamburger buns. Arrange the bottom halves of the buns on a baking sheet lined with parchment paper or aluminum foil.
05 -
Spoon shredded chicken mixture onto each bun bottom and top with a slice of mozzarella cheese. Place baking sheet under the broiler for 2 minutes, or until cheese is melted.
06 -
Place the top halves of the buns on each sandwich and serve immediately.