Preheat your oven to 400°F.
Heat a large skillet over medium-high heat. Add the ground turkey and cook for 5-7 minutes, breaking it apart as it browns. Stir in the taco seasoning and prepare according to the package directions, adding water if needed.
While the turkey cooks, cut the bell peppers into sixths, removing the stems and seeds to create scoop-shaped pieces. Arrange them cut-side up on a large baking sheet.
Spoon the taco meat evenly into each bell pepper, then top with the shredded cheese.
Bake for about 7 minutes, or until the cheese has melted and the peppers are warmed through but still slightly crisp.
While the peppers bake, make the guacamole by mashing the avocados with the lime juice, diced red onion, salt, pepper, and garlic powder until well combined.
Top the bell pepper nachos with the guacamole and your favorite toppings, such as diced tomatoes, diced red onion, sour cream, sliced jalapeños, and chopped cilantro. Serve immediately.