Place defrosted chicken breasts and into a crock pot and sprinkle them with ½ teaspoon of oregano and 1 teaspoon of garlic powder.
Add 1 cup of marinara sauce on top of the chicken.
Cook for 4 hours on high and shred chicken. Combine with the sauce.
Cut open 12 slider rolls and place them in a greased casserole pan. Try to slice the sliders so that the tops are taken off but they are still attached to each other on the bottom.
Spread the shredded, saucy chicken onto the halves of the slider rolls.
Spread 2 cups of shredded mozzarella cheese over the chicken.
Place the top of the buns over the mozzarella. Brush with the melted butter and sprinkle with a mix of Parmesan cheese, Italian seasoning and garlic powder.
Bake for 15 minutes at 350 degrees or until the cheese has melted and tops have started to brown.
Slice the sliders and serve.