Top four slices of bread with monterey jack, tortilla chips, jalapeno peppers and pepper jack. Top with remaining bread. Spread the outsides of sandwiches with butter.
Toast one sandwich, covered, in a large skillet over medium heat for 2-3 minutes or until the side is golden brown.
Flip sandwich; cook, uncovered, 2-4 minutes longer or until bread is lightly golden brown and cheeses are melted.