Preheat your oven to 350°F (175°C).
Line a large baking sheet with parchment paper or foil.
Spread the 3 cups of tortilla chips evenly across the baking sheet.
Evenly distribute the 2 cups of cooked shredded smoked brisket over the tortilla chips.
Generously sprinkle 1 1/2 cups of grated cheddar cheese over the brisket and chips.
Scatter the diced jalapeño and diced tomato over the cheese.
Place the baking sheet in the preheated oven and bake for about 10-15 minutes, or until the cheese is melted and bubbly.
While the nachos are baking, dice the avocado and set it aside.
Once the nachos are out of the oven, top them with the diced avocado, a generous scoop of salsa, and a dollop of sour cream. Serve immediately and enjoy!