Preheat an oven to 180 degrees C. Place a sheet of aluminium foil onto a baking tray and lightly grease with cooking spray.
Place the turkey mince into a large mixing bowl and sprinkle with the chilli powder, salt, black pepper and Parmesan cheese. Add the egg, olive oil, chopped onion and the jalapeno chilli. Mix well with your hands until evenly blended, then sprinkle with the taco crumbs and bread crumbs. Mix again until the bread crumbs are incorporated. Form the meatball mixture into small balls and place onto the prepared baking tray.
Bake in the preheated oven until the meatballs have lightly browned and are no longer pink in the centre, about 40 minutes. Turn the meatballs over after 20 minutes to ensure even cooking.
Fill a large pot with lightly salted water and bring to a rolling boil over high heat. Once the water is boiling, stir in the spaghetti and return to a boil. Cook the pasta uncovered, stirring occasionally, until the pasta has cooked through but is still firm to the bite, about 12 minutes. Drain well in a colander set in the sink.
After you have flipped the meatballs, stir together the diced tomatoes, diced onion, spaghetti sauce and taco seasoning in a large saucepan. Bring to a simmer over medium-high heat, then reduce the heat to medium-low and simmer 10 to 15 minutes until the onion is tender.
Once the meatballs are ready, stir them into the sauce and cook 5 minutes longer. Spoon the meatballs and sauce over the spaghetti to serve.