Prepare vegetables (slice onions, cucumber, dill etc.)
Over medium heat, bring ½ cup of red wine vinegar to a low boil.
Add sweetener of choice and stir to dissolve.
Remove pan from heat and add onions to the hot vinegar, stir and let cool (you can store in a jar in the refrigerator for 1-2 weeks)
Assemble tzatziki sauce- to a small bowl, add yogurt, crushed garlic, shredded cucumber, dill and lemon. Stir to combine!
Add salt, pepper and garlic powder to taste, set aside.
Preheat skillet over medium heat.
Season chicken with salt, pepper and garlic powder (optional Italian seasoning).
Spray skillet with nonstick cooking spray.
Cook chicken for 3-5 minutes on each side, or until cooked through.
Remove from heat and squeeze lemon over chicken breast.
Assemble pita pockets with chicken, marinated onion and tzatziki.