A broiler may melt the cheese on a platter of loaded nachos.
A broiler supplies intense heat from above, making it useful for melting cheese and lightly browning the top of a nacho platter. In the loaded-nachos preparation described by Wikipedia, tortilla chips are arranged on a platter, toppings such as meat and refried beans are added, and shredded cheese is placed over the top before the platter goes under a broiler.
The broiler is especially suited to nachos because cheese melts quickly under direct radiant heat. It can also create browned spots and bubbling edges, although the chips must be watched carefully because they can become overly crisp or burn. A salamander, the commercial overhead broiling unit associated with the origin story of nachos, performs a similar job in professional kitchens.
After the hot platter comes out, cooks usually add cold toppings such as lettuce, tomatoes, salsa, and jalapeños. This two-stage method keeps the cheese melted while preserving freshness and texture in the garnishes. A broiler is therefore distinct from a deep fryer, pressure cooker, or steamer, none of which is the appliance named for this step.