Preheat oven to 375°F. Spray a 9x13 baking dish with cooking oil and set aside.
Season chicken cubes with salt, pepper, cumin, and smoked paprika. Heat 1 tablespoon olive oil in a large skillet over medium-high heat. Cook chicken for 5-6 minutes until golden and cooked through. Transfer to a bowl.
Add remaining olive oil to the skillet. Sauté onion and bell peppers for 4-5 minutes until softened. Add garlic and cook 1 minute more.
In a large bowl, mix cream cheese and sour cream until smooth. Stir in fajita seasoning, diced tomatoes, and half of each cheese.
Add cooked chicken and vegetables to the cream cheese mixture. Stir to coat evenly. Pour into prepared baking dish and spread evenly.
Top with remaining Monterey Jack and cheddar cheese. Bake for 20-25 minutes until cheese is melted and bubbly.
Let rest 5 minutes before serving. Garnish with fresh cilantro and serve with lime wedges.