In a large pot over high heat, bring the 6 cups chicken broth to a boil.
Add 2 tablespoons ground mustard and 16 ounces elbow macaroni. Reduce heat to medium-high and cook, stirring occasionally, for 8–9 minutes, or until the pasta is al dente.
Turn off the heat and do not drain. Stir in 3 cups shredded cheddar cheese, 3 cups shredded pepper jack cheese,2 (7 ounce cans) diced green chiles and 1/2 cup heavy cream until the cheese is fully melted and forms a smooth sauce.
Season with salt and pepper to taste. Serve immediately