Chicken Spaghetti

Name: Chicken Spaghetti
Ingredients: 8 ounces spaghetti; 2 cups grape tomatoes, halved lengthwise; 2 jalapenos, stemmed, seeded, and halved lengthwise; 4 cloves garlic, left whole; 1/2 yellow onion; 2 tablespoons (1/4 stick) unsalted butter; 2 tablespoons all-purpose flour; 2 cups whole milk, plus more as needed; 2 cups (8 ounces) shredded cheddar cheese; 2 cups (8 ounces) shredded Monterey Jack cheese; 1/2 teaspoon ground cumin; 1/4 teaspoon cayenne; 1/2 cup chopped fresh cilantro, plus more for garnishing; 2 teaspoons fresh lime juice; Salt and black pepper; 4 cups shredded cooked chicken