Bring a large pot of salted water to a rolling boil over high heat. Once boiling, add spaghetti and cook until al dente, about 8-10 minutes. Stir occasionally to prevent sticking.

While spaghetti cooks, seed and chop fire-roasted hatch chiles and finely dice onion.

In a large pan, heat olive oil over medium heat. Add diced onion and sauté for 3-5 minutes until soft and translucent.

Add minced garlic to the pan and cook for another minute until fragrant.

Stir in chopped hatch chiles, vegetable broth, sea salt, and chili powder into the pan. Cook for 3-5 minutes until slightly thickened.

Lower the heat and mix in Monterey Jack cheese, sour cream, and chopped cilantro (if using) about 2 minutes before spaghetti is finished.

Gradually pour in reserved pasta cooking water to loosen the sauce to the desired consistency and then remove from heat.

Drain the cooked spaghetti and add it to the pan with the creamy sauce. Toss until every strand is coated.

Let the mixture rest off the heat for a few minutes to allow the sauce to thicken.

Transfer to serving plates and garnish with extra chopped cilantro, crumbled cotija cheese, and sprinkle with chili powder before serving.