Add the meatballs, marinara, and water to the Instant Pot. Pressure Cook-Normal-High Pressure for 4 minutes. Make sure the valve is in the “sealing” position.
Once finished, manually release the pressure. Once depressurized, remove lid and stir in shredded mozzarella.
Assembling Sliders
Place 1-2 meatballs in each slider bun, top with additional mozzarella (if desired).
In a small bowl, combine topping ingredients and brush over the top of each bun. Serve immediately.