01 -  Set oven to 400°F and allow to fully preheat. 
 02 -  Combine pulled pork and BBQ sauce in a small saucepan over medium heat; stir until evenly heated, approximately 3 to 4 minutes. 
 03 -  Spread tortilla chips in a single layer on a large baking sheet. 
 04 -  Distribute warmed BBQ pulled pork evenly over the chips; sprinkle both cheddar and Monterey Jack cheeses generously on top. 
 05 -  Place baking sheet in oven and bake for 7 to 10 minutes until cheese is fully melted and bubbly. 
 06 -  Remove from oven; scatter red onion, jalapeño slices, diced tomatoes, and cilantro over the nachos. 
 07 -  Drizzle with sour cream and scatter diced avocado, if desired; serve immediately with lime wedges.