Start by placing the thinly sliced yellow onion at the bottom of your slow cooker.

In a separate bowl, combine minced garlic, chicken broth, olive oil, dried oregano, paprika, salt, and black pepper. Whisk until well blended.

Carefully place the chicken breasts on top of the sliced onions, then pour the seasoning mixture evenly over the chicken.

Cover the slow cooker and set it to low for 6-8 hours or high for 3-4 hours until the chicken shreds easily.

Once cooking is complete, use two forks to shred the chicken directly in the slow cooker, and mix with the caramelized onions and juices.

Warm the pita bread, fill each piece with the chicken mixture, top with tzatziki sauce, and add fresh tomatoes, cucumbers, and red onions.