Preheat the oven to 375 degrees and lightly grease a loaf pan.
In a large bowl, combine the ground beef, diced jalapeños, shredded cheddar, egg, diced onion, minced garlic, milk, salt, and black pepper. Mix with your hands until the ingredients are evenly distributed.
Press the mixture into the prepared loaf pan and smooth the top.
Bake for 50 minutes until the internal temperature reaches 160 degrees. Remove from the oven and let the meatloaf rest for 10 minutes.
While the meatloaf rests, stir together the diced tomatoes, chopped cilantro, diced red onion, lime juice, and salt in a small bowl to make the fresh salsa.
Slice the meatloaf and top each serving with a spoonful of salsa.