Combine all marinade ingredients in a small bowl and pour into the crockpot.
3 Tbsp red wine vinegar, 1 Tbsp olive oil, 3 cloves garlic, ½ white onion, ½ lemon, ¾ cup chicken broth, 1 Tbsp dried oregano, 1 tsp salt, ½ tsp black pepper
Add chicken to the crockpot.
2 lbs boneless skinless chicken breasts
Cook on low for 6-8 hours or high for 3-4 hours.
While the chicken is cooking, mix together (or blend) all of the ingredients for the tzatziki sauce and refrigerate.
1 cup plain nonfat greek yogurt, ½ English cucumber, 1 clove garlic, 1 Tbsp fresh dill, ½ lemon, 1 Tbsp olive oil, salt
Once the chicken is cooked, shred it in the crockpot.
Assemble the gyros by placing the chicken into a warm naan and topping with the tzatziki, tomatoes, onion and cucumbers.
for serving: naan, tomatoes, red onion and cucumber