Heat olive oil in a large saute pan over medium-high heat. Add tilapia and cook 3 minutes on each side, turning once, or until the fish flakes easily with a fork. Remove from heat and transfer the fish to a separate plate to cool. Use a fork to flake the fish into bite-sized pieces.
While the fish is cooking, spread the chips out evenly on a large baking sheet. Sprinkle evenly with the cheese. Place the sheet in the oven under the broiler until the cheese is melted, about 1 minute. (Watch the oven carefully so that the cheese doesn’t burn.) Remove, then top the chips evenly with the mango slaw, bite-sized tilapia, and optional toppings.
Serve warm.
To Make The Mango Slaw:
Toss all ingredients together in a large bowl until combined. Use immediately on the nachos.