Preheat oven to 400°F (200°C). Line a large rimmed baking sheet with parchment paper or foil for easy cleanup.
Heat olive oil in a large skillet over medium-high heat. Add diced chicken and taco seasoning. Cook for 5-7 minutes, stirring occasionally, until chicken is cooked through, no longer pink, and reaches an internal temperature of 165°F (74°C). Remove from heat.
Spread half of the tortilla chips in an even layer on the prepared baking sheet. Sprinkle with 1 cup of cheese. Top with the cooked chicken and black beans, distributing evenly. Add the remaining chips on top, then the remaining cheese and sliced jalapeños.
Bake for 8-10 minutes, until the cheese is fully melted and bubbly. Keep an eye on it so the chips don't burn.
Remove from oven and immediately scatter fresh diced tomatoes and cilantro over the top. Dollop with sour cream and guacamole, or serve on the side for dipping. Serve hot with salsa if desired.