Cook the rotini pasta according to package instructions in a large pot of salted boiling water. Drain and set aside.
In the same pot, heat the olive oil over medium heat. Add the diced onion and sauté for about 3-4 minutes until softened.
Add the minced garlic and cook for an additional 1 minute until fragrant.
Stir in the can of diced tomatoes with green chilies, heavy cream, chili powder, cumin, salt, and pepper. Bring the mixture to a simmer.
Reduce the heat to low and stir in the cooked pasta, mixing well to coat.
Add the shredded cheddar cheese and stir until melted and creamy.
Remove from heat and let it sit for a couple of minutes to thicken slightly.
Serve warm, garnished with fresh cilantro if desired.