Preheat the oven to broil 450°F. Cut tilapia and season.
Heat olive oil in a large saute pan over medium-high heat. Add the tilapia cubes and cook 1 to 2 minutes, turning and stirring to cook throughout until the fish flakes easily with a fork. Remove from heat and transfer the fish to a separate plate to cool.
Saute' peppers and onion until soft.
While the fish is cooking, spread the chips out evenly on a large baking sheet.
Top with fish.
Top with peppers and onions
Finally, sprinkle cheese over the nachos evenly.
Place the sheet in the oven under the broiler until the cheese is melted, about 1 minute. Do not step away, they will burn quickly.
Remove from the oven, then top the chips evenly with additional toppings if desired or serve as is.
Notes
Finish with your favorite toppings: lettuce, sour cream, tomatoes, cilantro, salsa, etc