In a medium bowl combine diced tomatoes, diced onion, chopped cilantro, minced jalapeño, 1 tablespoon lime juice, 1/2 teaspoon salt and 1/4 teaspoon black pepper. Stir gently, taste and adjust seasoning. Refrigerate until ready to serve to let flavors meld (at least 10 minutes).

Guacamole

Halve and pit avocados, scoop flesh into a bowl and mash to desired texture. Add 1 tablespoon lime juice, 1/2 teaspoon salt, 2 tablespoons very finely diced onion, 1 tablespoon chopped cilantro and 1/2 teaspoon minced jalapeño if using. Stir to combine and taste; adjust salt or lime. Cover with plastic touching surface or refrigerate briefly until assembly.

Protein Preparation

If using ground beef

Heat 1 teaspoon olive oil in a skillet over medium-high heat. Add 1 lb raw ground beef and cook, breaking up with a spoon, until no longer pink, about 6–8 minutes. Drain excess fat if desired. Sprinkle chili powder, cumin, garlic powder, onion powder and 1/2 teaspoon salt over the meat, add 2 tablespoons water, stir and simmer 1–2 minutes until seasoning is incorporated. Taste and adjust seasoning. Keep warm.

If using chicken

If you have raw chicken: toss 1 lb chicken with 1 tablespoon olive oil, 1 teaspoon chili powder, 1/2 teaspoon cumin, 1/2 teaspoon garlic powder and 1/2 teaspoon salt. Cook in a skillet over medium heat 6–8 minutes per side (depending on thickness) until internal temperature reaches 165°F (74°C). Let rest 5 minutes, then shred or dice. If using leftover cooked chicken, warm in a skillet with the spices briefly to coat.

Assemble & Melt Cheeses

Preheat oven to 400°F (200°C). Spread 8 cups tortilla chips in an even layer on a large rimmed baking sheet or ovenproof platter. Scatter half of the shredded cheddar and half of the Monterey Jack over chips. Spoon the warmed protein evenly over the chips. Top with remaining cheeses to cover most chips and protein. Bake in preheated oven 5–8 minutes until cheese is melted and bubbling. For crisper chips, broil 30–60 seconds watching closely.

Finish & Serve

Remove nachos from oven. Dollop guacamole and spoon pico de gallo over the melted cheese (alternatively serve pico and guacamole on the side). Add 1/2 cup sour cream either in spooned dollops or drizzled. Garnish with pickled jalapeños and sliced green onions if using. Serve immediately while hot.