Combine pepper, garlic, ginger, cilantro, lime juice, soy sauce, allspice, 5-spice powder, nutmeg, salt, and pepper in a food processor. Pulse several times until mixture is very finely chopped.
Scrape processed mixture into a large bowl and add chicken, panko, and egg. Gently knead until combined and form into 1-in meatballs.
In a large skillet over medium-high heat, heat vegetable oil and swirl pan to evenly coat. Add meatballs to pan and sear on all sides, turning occasionally with a tongs until meatballs are golden brown. Transfer meatballs to a clean plate and set aside.
Pineapple Sauce
Wipe pan clean and add pineapple juice, brown sugar, ketchup, ginger, garlic, and cornstarch-water mixture. Stir sauce over medium heat until bubbly and slightly thickened. Season sauce with salt and pepper to taste.
Add meatballs and diced pineapple to sauce and toss until evenly coated. Cover pan and allow to simmer over medium-low heat 5-10 minutes until meatballs register 165F. Serve meatballs warm over hot rice with cilantro on top and enjoy!