Preheat the oven to 350ºF and position a rack in the center.

Spread half of the 3 cups tortilla chips in a single even layer on a rimmed baking sheet.

Evenly scatter half of the 2 cups cooked shredded smoked brisket (or oven-cooked brisket) over the chips, then sprinkle half of the 1 1/2 cups grated cheddar cheese and half of the deseeded, diced jalapeno on top.

Repeat: add the remaining tortilla chips in a single layer, then top with the remaining brisket, remaining grated cheese, and remaining diced jalapeno.

Bake on the center rack until the cheese is fully melted and the brisket is heated through, about 12 to 15 minutes.

Remove the nachos from the oven and immediately scatter the diced tomato and diced avocado over the top.

Serve hot, offering salsa and sour cream on the side or spooned over the nachos as desired.