Pound out chicken thighs between two pieces of parchment paper.
Whisk together garlic powder, Italian seasonings, salt, pepper and minced dried onion.
Rub both sides of chicken thighs with seasoning. Set aside.
Place garlic cloves and oil in the bottom of the crock pot and spread around all over.
Divide the basil leaves and place 4-5 in the middle of each thigh.
Top with ½ tablespoon of sun dried tomatoes for each thigh.
Place a slice of mozzarella over each thigh and roll up. Secure with toothpick.
Place thighs into slow cooker.
Pour balsamic vinegar over thighs.
Cover and cook on high 3 hours or low 6 hours.
Remove toothpicks before serving.