Cook the spaghetti according to package instructions until al dente.
In a large skillet, heat olive oil over medium heat.
Add chopped onion and sauté until translucent.
Stir in minced garlic and cook for 1 minute.
Add sliced bell pepper and cook until tender.
Pour in the diced tomatoes and add taco seasoning.
Mix in corn and black beans, stirring well.
Simmer the sauce for about 5-7 minutes.
Drain the spaghetti and add it to the skillet.
Toss everything together, seasoning with salt and pepper to taste.
Garnish with fresh cilantro before serving.