Preheat the oven to 350 degrees F (175 degrees C). Grease a 9x5-inch loaf pan.

Mix together croutons and salsa in a large bowl; set aside to soften, about 15 minutes.

Heat olive oil in a skillet over medium heat. Cook and stir onion, jalapeño pepper, and garlic in hot oil until onion is translucent, 5 to 8 minutes. Remove from heat.

Mix ground chicken, ground pork, pepper Jack cheese, cilantro, egg, taco seasoning, and Worcestershire sauce into crouton mixture; mash any unbroken croutons. Mix into onion mixture in the skillet, then transfer to the prepared loaf pan.

Mix together barbecue sauce and brown sugar in a small bowl, stirring until sugar has dissolved. Brush over meatloaf. Fold a 12-inch-long piece of aluminum foil into a tent and place over meatloaf.

Bake in the preheated oven until no longer pink in the center and the juices run clear, about 1 hour. Remove the foil tent for the last 10 minutes of baking. An instant-read thermometer inserted into the center of loaf should read at least 165 degrees F (75 degrees C). Remove meatloaf from the oven, cover with foil, and let stand for 15 minutes before serving.