Heat the grill to medium-high heat. Using long-handled tongs, lightly oil the grill grates by dipping a paper towel or a cut onion into Grapeseed Oil or another high smoke point oil and rubbing it on the grill grates.
Pat the swordfish dry with a paper towel, and season on both sides with a small amount of oil, salt, fresh pepper, and a small sprinkling of cumin. (I pour a small amount of the oil in the palms of my hands and rub my hands with the oil on the fish. Sprinkle the oiled fish with salt, pepper, and cumin, and rub lightly with your hands to get the spices to stick to the fish.)
When the grill is hot, place swordfish onto the grates. For an attractive crosshatch of grill marks, rotate the steaks 90 degrees after about 2 minutes on each side. Grill the swordfish for about 5 minutes per side, depending on the thickness of the fish, or until tender and cooked through when pierced with a knife. You can also test for doneness by pressing the swordfish steak with your finger; it should break into clean flakes when fully cooked. Remove the swordfish from the grill. Remove skin (if any) from fish, and flake into large pieces with a fork. Set aside.
Using an oven-proof plate, place a layer of tortilla chips on the bottom of the plate. Sprinkle shredded pepper jack cheese over the chips. Top with spoonfuls of salsa and sprinkle with corn. Place a second layer of chips over the top of the mound. Top with cheese, salsa, and corn as before.
(I've found that two layers of chips and goodies are perfect. More than two layers, and it's hard to get everything all melty on the inside of the mound).
Place plate of nachos inside the grill. Adjust the heat of the grill so that the plate is in indirect heat. (We have four burners in our grill, so I turned the two outside ones on medium-high, turned off the two inside burners, and placed the nachos in the middle of the grill.) Cook on indirect heat until the cheese on the top is browned and bubbly, about 15-25 minutes, checking frequently, as grill heats can vary widely.
Remove from grill, and top with flaked swordfish and chopped chives.
Serve Swordfish nachos with homemade guacamole and spicy sour cream. Oh, and lots of napkins!
*Spicy sour cream is simply equal parts hot salsa and sour cream, thin with a little milk if desired. So yummy!