Preheat oven to 350 degrees F.
Cut the tops off the bell peppers and remove the seeds and membranes. Place the peppers cut-side up in a lightly sprayed baking dish.
Add the ground beef to a nonstick skillet. Break apart the ground beef and add the onion. Cook until the ground beef is no longer pink. Drain any excess grease.
Stir in the cauliflower rice, Rotel, taco seasoning, garlic powder, cumin, salt, and pepper. Simmer 3-5 minutes.
Spoon the mixture evenly into each bell pepper. Cover with foil and bake for 35 minutes.
Remove foil, sprinkle cheese on top, and bake an additional 10 minutes, until peppers are tender and cheese is melted. Garnish with fresh cilantro and serve.