Heat a skillet over medium-high heat. Add andouille and cook for 2 minutes. Add onion and cook for 2 minutes more. Add bell peppers and cook for 2 minutes more. Remove from heat and stir in celery.
Line a baking sheet with foil and place tortilla chips on top. Cover chips with the sausage mixture.
Place shrimp in a bowl; add oil and seafood seasoning. Stir to coat. Place shrimp in the same skillet and cook over medium-high heat for 3 minutes. Scatter shrimp on top of the sausage mixture. Sprinkle Colby Jack cheese over the nachos.
Set an oven rack about 6 inches from the heat source and preheat the oven's broiler to low. Broil nachos until cheese has melted, about 3 minutes.