Preheat oven to 400 degrees F. Spray a 9-inch by 13-inch baking dish with nonstick cooking spray, set aside.
Add the diced tomatoes and tomato sauce into the bottom of the Instant Pot. Add the Italian seasoning, garlic powder, oregano, salt and pepper. Stir to combine.
Add the chicken and turn to coat in the sauce.
Close and lock the Instant Pot lid, and place the steam valve onto sealed. Cook on manual high pressure for 15 minutes.
Once the Instant Pot has finished cooking, allow to naturally release for 5 minutes and then quick release any remaining steam.
Remove the chicken, set the Instant Pot to the Saute function, and cook for 2-4 minutes to reduce the cooking liquid.While the liquid is reducing, shred the chicken using 2 forks.
Keep the Instant Pot on WARM and return the shredded chicken to the sauce, stirring to full coat the chicken. Allow to sit in the sauce while preparing the slider buns in the oven.
Mix together melted butter and minced garlic. Place the bottoms of the slider rolls into the baking dish and lightly brush the tops with the melted butter mixture. NOTE: do not skip this step or the slider may become soggy. Place in the oven for 4 minutes, until slightly toasted, and remove. (Leave oven on).
Remove the chicken from the Instant Pot with a slotted spoon allowing excess sauce to drain into the Instant Pot.
Evenly distribute the chicken on the rolls (about 2 tablespoons each).
Reserve 1/4 cup of the Parmesan cheese and sprinkle the rest evenly on the chicken. Add a slice of the quartered provolone cheese on top of each slider.
Place the slider bun tops back on and brush again with the remaining melted butter mixture. Sprinkle the remaining Parmesan cheese across the bun tops.
Put the sliders back into the oven for 4-5 minutes, to melt the cheese and slightly toast the slider tops. Remove, sprinkle with the chopped fresh parsley and serve warm!