Cheesy Pepperoni-Pizza Chicken Melts

Ingredients

• 4 boneless, skinless chicken breasts (6 ounces each)
• 2 cups pre-shredded mozzarella, divided
• 1 teaspoon garlic powder
• 2 teaspoons avocado oil
• 1 teaspoon minced parsley
• ½ teaspoon salt
• ½ teaspoon Italian seasoning
• 32 slices pepperoni
• ¼ cup grated Parmesan cheese
• 1 cup pizza sauce
• 1 small onion, thinly sliced
• 1 cup sliced mushrooms