Slice the spaghetti squash lengthwise and remove the seeds. Roast the squash in a 425°F oven until cooked through - about 40 minutes.
Sauté the red pepper and onion in a drizzle of olive oil until soft. Set aside.
Brown the ground turkey. Mix in taco seasoning, tomato paste, and water. Stir until combined.
Add onion and red peppers, black beans, corn, and Rotel tomatoes to the meat. Mix well and heat through.
Top the spaghetti squash with the meat / bean mixture.
Garnish with a small amount of Mexican blend cheese and serve with Greek yogurt and sliced avocado.
* Percent Daily Values are based on a 2,000 calorie diet. Your daily value may be higher or lower depending on your calorie needs.