Heat olive oil in a large skillet or Dutch oven over medium-high heat. Add ground beef and onion. Cook, breaking up the beef with a wooden spoon, until the beef is browned and the onion is softened, about 6-8 minutes. Drain any excess fat.

Add minced garlic and taco seasoning to the skillet. Cook for 1 minute more, stirring constantly, until fragrant.

Pour in 1/2 cup water, diced tomatoes (undrained), rinsed black beans, and drained corn. Stir to combine. Bring the mixture to a simmer, then reduce heat to medium-low and let it cook for 5 minutes, allowing the flavors to meld.

Stir in the chicken broth and uncooked elbow macaroni. Bring the mixture to a boil, then reduce heat to low, cover, and simmer for 10-12 minutes, or until the pasta is al dente and most of the liquid has been absorbed, stirring occasionally to prevent sticking.

Remove from heat. Stir in the heavy cream, then gradually add the shredded cheddar cheese and Monterey Jack cheese, stirring until the cheese is melted and the sauce is creamy.

Let the pasta sit for 2-3 minutes to thicken slightly. Serve hot, garnished with fresh cilantro, sour cream, diced avocado, and pickled jalapeños, if desired.