Slice the zucchinis in half lengthwise and scoop out the center with a spoon to create boats. Set the zucchini flesh aside for later use.
In a large skillet, heat the olive oil over medium heat. Add the diced chicken, cooking until browned and cooked through, about 5-7 minutes.
Stir in the sliced bell peppers, red onion, and the reserved zucchini flesh into the skillet. Cook for another 5-6 minutes, until the vegetables are tender.
Add the chili powder, cumin, paprika, garlic powder, salt, and pepper to the skillet. Mix well to combine and let everything cook for an additional 2 minutes to marry the flavors.
Remove the skillet from heat and stir in half of the shredded cheese.
Place the zucchini boats in a greased baking dish. Fill each boat generously with the chicken fajita mixture.
Top each filled zucchini boat with the remaining shredded cheese.
Bake in the preheated oven for 20-25 minutes, until the cheese is bubbly and the zucchini is tender.
Garnish with freshly chopped cilantro and serve with lime wedges on the side.
Notes
Feel free to customize the vegetables or add more spices to taste.