Place the chicken in a large bowl. Season all over with salt and pepper. Add 2 cloves of garlic, parmesan, breadcrumbs and herbs. Mix gently until just combined.
Roll the mixture into 1-inch meatballs.
Heat the olive oil in a large (12-inch) oven-safe skillet or dutch oven over medium heat. You want this pan to be large enough for the orzo and stock too. Add the meatballs in a single layer and brown for 3 to 4 minutes. Flip gently and brown the other side for another 3 to 4 minutes. Shake the pan, tossing the meatballs around to keep their shape. Transfer the meatballs to a plate.
To the same pan, add the butter. Add in the orzo and stir. Cook, stirring often, until the orzo toasts and turns a bit golden. Stir in the other 2 garlic cloves. It will be very fragrant.
Pour the stock and 1 cup of the marinara in with the orzo. Nestle the meatballs back into the pan with the stock and orzo. Bring the mixture to a boil. Reduce it to a simmer and cover. Cook for 15 to 20 minutes, until the liquid is absorbed and the chicken reaches 165 degrees F internally. Scrape the bottom of the pan with a wooden spoon if necessary - it should not be hot enough to burn. I suggest checking after 12 to 15 minutes and going from there - because this will differ based on how high your “simmer” is!
Once the liquid is absorbed, add the remaining marinara in dollops all over the top. Pull apart the mozzarella and place it on top too.
Turn the broiler on in your oven. Broil for 1 to 2 minutes, just until the cheese has melted and is golden.
Remove the pan and top with parmesan and fresh basil. Serve!