Cook beef and bell pepper in a large nonstick skillet over medium-high heat until beef is browned; stir to crumble. Add salsa; bring to a boil. Stir in cilantro; keep warm.
Place 1 cup lettuce on each of 4 plates; top with 1 cup meat mixture. Sprinkle each serving with 1/2 cup tomato, 1/4 cup cheese, 1/4 cup chips, and 1 tablespoon onions.