Set your Ninja Woodfire Grill to the smoker setting and preheat it to 225°F (107°C). This ensures the grill is at the right temperature for smoking.

Trim any excess fat from the pork tenderloin. Pat the meat dry with paper towels to help the seasoning adhere better.

In a small bowl, combine the garlic powder, onion powder, paprika, salt, black pepper, brown sugar, thyme, and mustard powder. Rub the pork tenderloin with olive oil, then generously coat it with the spice mixture, pressing it into the meat to ensure even coverage.

Place the seasoned pork tenderloin on the preheated grill. Close the lid to maintain a consistent temperature and smoke flow.

Smoke the pork tenderloin at 225°F (107°C) for about 1.5 to 2 hours, or until the internal temperature reaches 145°F (63°C) for medium-rare. Use a meat thermometer to check the internal temperature.

Once the pork reaches the desired internal temperature, remove it from the grill and let it rest for 5-10 minutes. This allows the juices to redistribute throughout the meat, ensuring a moist and flavorful result.

After resting, slice the pork tenderloin into medallions. Serve immediately, and enjoy the tender, flavorful smoked pork.